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Executive Health and Safety

Investigation of potential exposure to carcinogens and respiratory sensitisers during thermal processing of plastics

Prepared by Health and Safety Laboratory for the Health and Safety Executive 2010

RR797 Research Report



John Unwin, Chris Keen & Matthew Coldwell Health and Safety Laboratory Harpur Hill Buxton Derbyshire SK17 9JN

This work was carried out in support of HSE’s FIT3 Disease Reduction Programme Cancer Project’s aim to develop a strategy to reduce the incidence of occupational cancer in Great Britain. As part of this strategy, HSE has initiated research that aims to deliver evidence that will help to identify carcinogens of concern, improve control of exposure to carcinogens at work and provide a baseline for evaluating strategies for intervention.

Earlier, in 2005-7, HSL characterised the exposure profiles of a selected group of occupational carcinogens and determined baseline exposures with which to compare future levels. The project identified the potential for exposure to carcinogens in the thermoplastic processing and finishing industries however there was a scarcity of published quantitative exposure data. A number of laboratory and other studies had shown that carcinogens could be generated from the processing of thermoplastics in some situations but further investigation was required to establish the levels of exposure that may originate in the industrial setting.

The report describes the results of sampling for carcinogens and respiratory sensitisers at ten large processing plants. The measurement strategy used was sufficiently broad in scope to take into account the presence of respiratory sensitisers and respiratory irritants as well as carcinogens. The findings demonstrate that compliance with HSE guidance achieves adequate prevention and control of exposure in the common thermoplastic processes considered. This report will be helpful to smaller plants operated by small and medium enterprises who undertake the same processes albeit on a smaller scale.

This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy.

HSE Books

© Crown copyright 2010

First published 2010

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording or otherwise) without the prior written permission of the copyright owner.

Applications for reproduction should be made in writing to:Licensing Division, Her Majesty’s Stationery Office,St Clements House, 2-16 Colegate, Norwich NR3 1BQor by e-mail to [email protected]

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CONTENTS

1 INTRODUCTION ..............................................................................................1

2 ENGAGEMENT OF INDUSTRY STAKEHOLDERS .....................................5

3 SITE VISITS......................................................................................................73.1 Range of sites visited....................................................................................73.2 Measurement protocol ..................................................................................7

4 RESULTS..........................................................................................................94.1 Site 1 – PVC compounding and extrusion...................................................94.2 Site 2 – PE and PP extrusion and blown film............................................104.3 Site 3 – PE and recycled PE extrusion and blown film.............................114.4 Site 4 – PE, PP, PS recycling and extrusion.............................................124.5 Site 5 – PET extrusion and blow injection moulding.................................134.6 Site 6 – ABS vacuum forming of sheet......................................................144.7 Site 7 – PVC extrusion................................................................................154.8 Site 8 – EPS blow moulding and hot wire cutting .....................................164.9 Site 9 - PVC/chlorinated PVC alloy thermoforming ..................................174.10 Site 10 – PVC welding ................................................................................18

5 DISCUSSION..................................................................................................205.1 Materials and processes investigated .......................................................20

6 CONCLUSIONS..............................................................................................236.1 Main findings from the measurement survey ............................................236.2 Adequacy of Control Measures..................................................................23

7 REFERENCES................................................................................................25

8 APPENDIX 1 – ADDITIVES AND DEGRADATION PRODUCTS.............27

9 APPENDIX 2 - AIR MONITORING RESULTS.............................................30

10 APPENDIX 2 - SAMPLING AND ANALYTICAL TECHNIQUES............4010.1 Introduction..................................................................................................4010.2 Low volume sampling .................................................................................4010.3 High volume sampling ................................................................................40

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EXECUTIVE SUMMARY



This study will also inform a parallel programme of work on respiratory disease because the measurement strategy used was sufficiently broad in scope to take into account the presence of respiratory sensitisers and respiratory irritants as well as carcinogens.

Objectives

• To make relevant industry contacts and scope out key areas of the thermoplastic processing to select a suitable number of workplaces to visit

• To investigate the selected sites and carry out screening measurements for carcinogens and respiratory sensitisers

• Carry out occupational hygiene assessments for each process investigated.

• To assess the analytical data and determine the potential for exposure to carcinogens and respiratory sensitisers across the thermoplastics processing sector.

Main Findings

• The levels of carcinogens detected in the process fume at the sites investigated were found to be either low or not detectable.

• Where low levels of carcinogens or potential respiratory sensitisers were found these were at concentrations 2 – 3 orders of magnitude below any respective WEL.

• The maximum concentrations of carcinogens found at the sites visited were: benzene 3(R45) 11 ppb; formaldehyde (R40) 9 µg/m ; naphthalene (IARC 2B) < 100 ng/m3; and,

other carcinogenic polycyclic aromatic hydrocarbons (IARC 1, 2A and 2B) all < 1 ng/m3.

• All substances detected in this study were measured at levels below 10% of their respective WEL, demonstrating the low levels of process fume encountered.

• The low levels of total inhalable particulate measured (values from all sites were below 1.15 mg/m3) and the low concentration of all other substances measured, demonstrates

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the low levels of fume generated and the effective temperature control of the respective thermal processing operations.

• A notable absence of monomers was found in the process fume, which is often a predictor of polymer degradation, and further supports the evidence for good temperature control and minimal generation of process fume at the sites investigated.

• At the majority of sites it was not always possible to clearly separate background environmental levels of contaminants from those generated from other procedures carried out at the site and those generated from the thermal processing activity of interest due to the low concentrations found.

• No known respiratory sensitisers (R42) were found at any of the sites investigated.

• Where low levels of respiratory irritants such as aldehydes, ketones and hydrochloric acid were found these were at concentrations 2 – 3 orders of magnitude below any respective WEL.

• The principal exposure controls employed at the sites investigated were a combination of process temperature control and forced mechanical dilution ventilation.

• Most processes at the sites investigated required very little operator intervention, which in itself reduced exposure risk.

• The use of LEV and RPE to control exposures to airborne contaminants generated by thermoforming processes was not commonplace at the sites visited.

• The measurement results indicate that no carcinogens, respiratory sensitisers or respiratory irritants were detected at levels of concern at any of the sites visited. This indicates that the strategies employed are adequate to control the risks associated with exposure to these agents.

Recommendations

The report describes the results of sampling for carcinogens and respiratory sensitisers at 10 large processing plants. It is recognised that these plants are not fully representative of the whole of the plastics processing sector which includes a large number of SMEs. However, the findings demonstrate that compliance with HSE guidance (HSE, 2002) achieves adequate prevention and control of exposure in the common thermoplastics processes considered. It will therefore also do so at smaller plants operated by SMEs who are undertaking the same thermoplastics processes albeit on a smaller scale.

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1 INTRODUCTION


HSE characterised the exposure profiles of a selected group of occupational carcinogens and determined baseline exposures with which to compare future levels at an early stage of the FIT3 Disease Reduction Programme Cancer Project (HSE, 2006). This study identified the potential for exposure to carcinogens in the thermoplastic processing and finishing industries. HSE considered there to be however a scarcity of published exposure data for plastics processing fume.

Thermoplastics are generally processed as pellets, granules or powders, sometimes containing many additives such as fillers, pigments, fire-retardants and stabilisers (see table 1A and appendix 1). The composition of the fume generated when the plastic is heated may be complex and will vary depending on the type of plastic, the formulation and the processing conditions. Tables 2A and 3A in appendix 1 clearly demonstrate the significant difference in type of degradation products from chemically similar polymers such as polyethylene and polypropylene degraded under laboratory conditions at typical processing temperatures. Where thermal processing is poorly controlled and recommended processing parameters such as temperature and residence time are exceeded then polymer breakdown can occur leading to the potential release of airborne contaminants resulting in irritation to the eyes, nose and lungs (HSE, 2002). Laboratory studies involving heating or vaporisation of polymers in processes such as hot gas welding and laser cutting (Sims et al., 1993) have shown that a range of airborne contaminants including carcinogens and respiratory irritants may be generated from commonly processed plastics. The results of this work are summarised in tables 4A and 5A of appendix 1.

Other unpublished laboratory studies carried out at the Health and Safety Laboratory (HSL), summarised in table 1, show the potential for the release of carcinogens and other emissions including respiratory sensitisers and irritants at temperatures near to processing temperatures for some common thermoplastics. Several carcinogens (HSE 2005 and IARC, 2009) are listed (R45, R40 and IARC categories 1 and 2) in table 1.Although no respiratory sensitisers were identified (R42) there are a wide range of compounds harmful by inhalation (R20), irritating to the respiratory system (R37), which may contribute to potential respiratory sensitisation. Other substances were also detected which may cause other adverse health effects such as sensitisation by skin contact (R43) and irritation to the eyes and skin (R36/38).

Although the International Agency for Research on Cancer (IARC) classification of a substance has no regulatory status in the UK, where IARC have classified a substance as carcinogenic the information is included in this report. The decision to include these carcinogens was made at the stakeholder workshop (McElvenny et al.,2007) held on 27th - 28th June 2006 to review progress with the HSE Occupational Cancer Epidemiology project and involved a team of eminent epidemiologists and statisticians who were evaluating the numbers of cancers in GB attributable to occupational causes.

Little is known of the potential for generating these emissions under real workplace processing conditions and there is very limited published research on the composition of plastic process fume in real workplace situations. One such study involved a number of plastics and processes

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that detected very low levels of acrylonitrile under certain conditions for the processing of acrylonitrile-butadiene-styrene (ABS) and benzene when processing nylon but little else of concern in terms of carcinogens, respiratory sensitisers or irritants (Forrest M et al., 1995). However, the measurement protocol for this study was very limited and certain classes of substances, for instance semi-volatile compounds such as polycyclic aromatic hydrocarbons (PAHs) and potential respiratory irritants such as volatile aldehydes and ketones would not have been detected. Other, more recent studies (Meijster et al., 2004) have focussed on a limited range of polymer types and found a wide range of substances in the process fume.

This project has striven to encompass as wide a range of industry as possible within the resources available and represents an investigation of different processes all utilising thermoformed plastic in different ways. The plastics thermoforming sector of industry consists predominantly of SMEs (85%). This report describes visits to a limited number (10) of co-operative businesses and is not representative of the industry as a whole. The findings of this work clearly demonstrate however that many common practices occur between large and smaller concerns and that compliance with HSE guidance (HSE, 2002) is reasonable, practicable and achievable. The challenge now is for SMEs to control exposures as well as these businesses.

Analyses of national mortality data by occupational group for the 1980s (Office of Population Census and Surveys, 1995, and Brown et al. 2007) showed an excess of male lung cancer deaths among plastics process workers; and an excess of female lung cancer registrations was also among this occupation during this period. Limitations in the occupational classification have prevented a more up-to-date assessment of mortality and cancer incidence for this occupation. Excesses of male deaths due to acute lymphatic leukemia and diabetes, and an excess of male stomach cancer registrations were also seen among the occupation "plastic goods makers", however, no excess deaths were seen for these diseases in this occupation in the latest analysis of deaths during 1991-2000 (Office for National Statistics, 2009).

HSE considered that: • due to the past excess of cancers reported in the plastics processing industry; • the potential for exposure to carcinogens in the thermoplastic processing and finishing

industries; and, • the findings of earlier laboratory studies;

there was a need for the work described in this report.

The objectives of the work were:

• To make relevant industry contacts and scope out key areas of thermoplastic processing to select a suitable number of workplaces to visit.

• To investigate the selected sites and carry out screening measurements for carcinogens and respiratory sensitisers.

• To carry out occupational hygiene assessments for each process investigated.

• To assess the analytical data and determine the potential for exposure to carcinogens and respiratory sensitisers or irritants across the thermoplastics processing industry.

The wide range of polymers, copolymers, additives and thermal processing methods meant that any study would be restricted to a small sample of manufacturing operations. The principal aim of the preliminary work, involving stakeholder discussion, was to allow the site visits to focus on the polymers and processes where it was considered most likely that there was greatest

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potential for generation of carcinogens, respiratory sensitisers and irritants. The measurement techniques adopted for the screening of substances found in the fume were of sufficient scope to capture a range of data on carcinogens, respiratory sensitisers and irritants but could not be exhaustive because of the potential for a large number of possible analytes.

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Table 1. Laboratory study of major thermal breakdown products of some common thermoplastics at 400 OC *

Polymer Type Thermal degradation products (Helium atmosphere)**

Risk Phrases for key health effects (HSE, 2005, IARC, 2009)

Polyvinylchloride (PVC)

Benzene Hydrogen chloride Methylmethacrylate Toluene Styrene Naphthalene Indene Methanol Methyl chloride Phenanthrene

45, 46, 23, 24, IARC 1.*** 23 37/38, 43. 20, 38, 48, 63. 36/38. IARC 2B --. 40, 48/20. -

Polypropylene (PP)

Pentane Propane Butane Dimethylheptane Methylpentane Alkenes

------

Low density polyethylene (LDPE)

Butane Butene C5- C14 primary alkenes C5-C14 n-alkanes C2-C7 aldehydes 1-Pentadecene Toluene Cyclohexanone

------20, 38, 48, 63.

Polystyrene (PS)

Styrene Benzaldehyde Benzene Toluene Methystyrene Butene Acetaldehyde C4-C6 aldehydes Ethylbenzene

36/38. -45, 46, 23, 24, IARC 1. 20, 38, 48, 63. --36/37, 40. -20.

Polyacrylonitrile-butadiene-styrene (ABS)

Styrene 1,3-Butadiene Acrylonitrile 4-Vinyl-1-cyclohexene

36/38. 45, 46, IARC 1. 45, 23/24/25, 37/38, IARC 2B -

Polymethyl methacrylate (PMMA)

Methylmethacrylate Methanol

37/38, 43.

*HSL unpublished work. ** Low molecular mass compounds such as formaldehyde and acetaldehyde would not be detected by the techniques used in this analysis. ***Risk phrases in bold are compounds which may pose a risk of cancer or irritation to the respiratory system. Key for risk phrases used in table 1. R20 - harmful by inhalation R23 - toxic by inhalation R24 - toxic in contact with skin R23/24/25 - toxic by inhalation, in contact with skin and if swallowed R26 - very toxic by inhalation R36/37 - irritating to eyes and respiratory system R36/38 – irritating to eyes and skin R37/38 - irritating to the respiratory system and skin R38 - irritating to skin R43 - may cause sensitisation by skin contact R40 - limited evidence of carcinogenic effect R45 - may cause cancer R46 – may cause heritable genetic damage R48 – danger of serious damage to health by prolonged exposure through inhalation R48/20 - harmful: danger of serious damage to health by prolonged exposure through inhalation R63 - possible risk of harm to unborn child IARC 1 – IARC classification, carcinogenic (IARC, 2009). 2A - IARC classification, probably carcinogenic to humans (IARC, 2009) 2B - IARC classification, possibly carcinogenic to humans (IARC, 2009)

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2 ENGAGEMENT OF INDUSTRY STAKEHOLDERS

Involvement of external stakeholders was sought to ensure that the survey effort could be targeted at key areas of the thermoplastic processing industry. Industry experts consulted were;

• Mr Trevor Oliver (Polymer Training Ltd);

• Dr Bryan Willoughby (Consultant, formerly employed by the Rubber and Plastics Research Association (RAPRA))

The industry experts possessed an extensive knowledge of the plastics industry and had contributed to earlier HSE guidance on the thermoplastic processing industry. They were influential in determining the range of polymers and process methods studied. Advice was also sought directly from other industry stakeholders such as the Plastics and Films Association (PAFA), The Welding Institute (TWI), and the Association of Industrial Laser Users (AILU). Discussions were held with a range of UK companies currently involved in plastics processing as well as HSE’s Manufacturing Sector.

Suitable processes and materials for investigation were identified by the stakeholders on the basis of parameters such as:

• Materials in common use

• Potential to generate fume

• Representative range of manufacturing processes and recycling

• Number of workers exposed

• Throughput of polymer

A summary of the outcome of the consultation with stakeholders is given in table 2. These thermo-polymers and processes formed the basis for the scope of the measurement survey and were believed to encompass the greatest potential for exposure to fume, the largest number of potentially exposed workers, and were some of the commonest materials and processes in use. It was intended that the measurement survey should match these materials and processes as closely as possible but with the realisation that not all would be fully captured.

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Table 2. Materials and processes identified by stakeholders for study

Polymer Type

Polyvinyl chloride (PVC)

Polyethylene (PE)

Polypropylene (PP)

Polystyrene (PS)

Polymethyl methacrylate (PMMA)

Acrylonitrile butadiene styrene (ABS)

Polyethylene terephthalate (PET)

Potential fume generating process

Vacuum forming: Softened polymer sheet is reshaped under vacuum on heated former.

Laser cutting: Polymer vaporisation during cutting.

Extrusion: Molten polymer forced by a screw through a temperature-controlled die.

Sheet, film and bag manufacture: Film blowing after extrusion

Compounding: Hot mixing of polymer resin and additives and extrusion to pellet.

Injection moulding: Extruded molten polymer is forced into a cooled mould.

Welding: Heating of rigid polymer profiles before compression mating of joints

Recycling: Melting of recycled polymers and additives and extrusion to pellet.

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3.1

3.2

3 SITE VISITS

RANGE OF SITES VISITED

Table 3 summarises the processes and materials actually investigated at the sites that participated in the measurement survey. For each site an Occupational Hygiene Site Visit Report (referenced in table 3), describing in detail the site, the processes involved, exposure controls and a summary of the air monitoring data was produced.

Table 3. Description of Plastic Process Fume Sites

Site reference number

Polymer(s) processed Process OH Report Reference No .

1 PVC compounding and extrusion

OH2008/LET/14

2 PE and PP extrusion, blown film OH2008/LET/15

3 PE, recycled PE extrusion, blown film, OH2008/LET/16 welding

4 Recycled PE, PP, PS recycling, extrusion OH2008/LET/17

5 PET extrusion, blow injection OH2008/LET/30 moulding

6 ABS vacuum forming of sheet OH2008/LET/44

7 PVC extrusion OH2008/LET/64

8 EPS blow moulding, hot wire OH2008/LET/45 cutting

9 PVC/chlorinated PVC alloy vacuum thermoforming OH2008/LET/70

10 PVC welding OH2008/LET/71

MEASUREMENT PROTOCOL

The measurement protocol was principally designed to identify the presence of carcinogens, respiratory sensitisers and irritants generated from the process rather than to assess personal exposure. On each site visit static sampling at 2 positions in close proximity to the process was employed. This allowed a broad array of highly sensitive screening techniques to be deployed at each position. Specific samplers for analytes of particular interest, including vinyl chloride monomer, butadiene, acrylonitrile and formaldehyde were employed. These analytes were identified from the literature (Forrest et al., 1995 and Sims et al., 1993) as possible components in fume generated during thermal processing of polymers. In addition, a range of generic sampling techniques were used to screen for various classes of substances. This included high

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volume sampling to target any low concentrations of semi-volatile organic compounds utilising a flow rate of 200 litres/minute. The measurement protocol is described in detail in appendix 2.

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4 RESULTS

The results for the static air monitoring carried out at the 10 sites are given in appendix 2. For comparison purposes the respective 8-hr TWA WEL values, where they exist for that specific substance are also shown. A summary of the sampling and analytical techniques used is given in appendix 3.

4.1 SITE 1 – PVC COMPOUNDING AND EXTRUSION

4.1.1 Overview of Process

The compounding operation involves the formulation of PVC compounds by adding a range of additives to PVC resin. There are 5 distinct compounding production units located in this plant. At the top floor of the plant the PVC powder (resin) is fed in from an external silo and additives are either added manually or from automated hoppers into weighing vessels. The mixture is then transported to a lower level to high-speed mixers. There are also addition points here where small amounts of additives, for example colorants, can be dispensed into the blend. At ground level the extrusion plant and the main parts of the cooling and bagging plants are situated. The blended raw materials are heated (to around 180 OC) in the barrel of the extruder where it is then passed through the extruder and die plate, cut into pellets and cooled. Following cooling the pellets are transferred by suction to the bagging plant.

4.1.2 Exposure controls

Local exhaust ventilation (LEV) was applied at the addition points where a contaminant release hazard was present. There was no requirement to provide LEV to any other part of the process. Visual observation of the area showed the hoods to provide adequate capture efficiency. There is a forced mechanical general ventilation system on one of the levels in the production area that will provide increased air movement. No other forced mechanical general ventilation measure was present on the other levels. Respiratory protective equipment (RPE) was used for certain tasks including cleaning and sample taking, but not for general production tasks.

4.1.3 Main findings

• Total inhalable particulate (TIP) levels were in the range 0.39 - 0.64 mg/m3.

• No evidence of exposure to toxic metals was found (all results <0.01 mg/m3).

3• The low concentrations of hydrogen chloride (<0.004 mg/m ) aldehydes (<0.08 µg/m3) and volatile organic compounds (all <0.5 ppm) and other semi-volatile materials were two or more orders of magnitude below any respective WEL.

• Vinyl chloride monomer was detected at concentrations of 3-20 ppb at values 2 to 3 orders of magnitude lower than the current UK WEL of 3 ppm.

• Several polycyclic aromatic hydrocarbons (PAHs) were detected at very low concentrations (<1ng/m3). Other than naphthalene (IARC 2B), none of the other 4 compounds detected are reported to exhibit carcinogenicity (IARC 2009).

• Azodicarbonamide (R42), an intermittently used additive was not detected in any air sample (<0.04 mg/m3).

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• Few of the other additives in use were detected (e.g. butylated hydroxytoluene <1ng m3).

4.1.4 General Conclusions

The low levels of TIP, VCM, hydrogen chloride and PAHs together with the absence of benzene, which is indicative of catastrophic PVC degradation, demonstrates that good temperature control of the compounding and extrusion processes was achieved. It is not clear whether the VCM originated from the process fume or from the adjacent PVC manufacturing plant. The company report there to be < 2 ppm residual free VCM trapped in the polymer resin from the manufacturing process which may potentially be released on thermal-processing. The levels of VCM found were typical of the environmental concentrations reported by the company for PVC manufacture. There was a notable low occurrence of semi-volatile materials, which potentially could have arisen from the use of additives in the compounding process as well as the process fume. The PAHs, usually associated with combustion processes were found at typical urban levels (UK Air quality Archive, 2008). There is no strong evidence to suggest that significant levels of carcinogens, respiratory sensitisers or irritants are being generated in the process fume.

4.2 SITE 2 – PE AND PP EXTRUSION AND BLOWN FILM

4.2.1 Overview of process

The company extrudes and blows molten polyethylene and polypropylene into a thin film suitable for use in food packaging. The extrusion hall comprises nine extruders. On the day of the visit only one of these was running polypropylene. There were a further 4 extruders running polyethylene. The bulk plastic pellet is stored in a number of external storage silos and is hard piped into the extrusion hall. The additives are stored within the main building in smaller silos. Small mobile hoppers are filled from these and located close to the extruders. The raw materials are automatically dosed and mixed (under heating at 180-200oC) in a rotary screw extruder and the blend passed through a filter plate which creates a pressure increase. It is then blown out into a continuous thin tubular shaped cylindrical film, which is air cooled and passed through rollers forming a double thickness sheet. The sheet is cut to separate and then passed over rollers where it is electrostatically charged to provide a “key” which aids the printing process. The finished film is wound and stored on large rolls.


The extrusion hall has a forced mechanical ventilation system. There is no LEV in place for the processes observed. RPE is not worn for general production tasks.

4.2.3 Main findings

• Total inhalable particulate levels were in the range <0.27 - 0.43 mg/m3.

• No evidence of exposure to toxic metals was found (all results <0. 01 mg/m3).

• Low levels of formaldehyde (2.3–3.4 µg/m3) were detected. This may be associated with thermal oxidation of the polymers, although there are other common sources of this substance.

• Several solvents (all <1ppm) were identified which may have originated from printing, laminating or other processes carried out in adjacent areas of the plant.

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• The concentrations of aldehydes, VOCs and other semi-volatile materials were generally several orders of magnitude below any WEL .

• Several PAHs were detected at typical urban concentrations (<1ng/m3), other than naphthalene (IARC 2B) none of these are reported to be carcinogenic (IARC 2009).


The low levels of oxygenated compounds such as aldehydes, ketones and alcohols found, demonstrate the lack of polymer degradation through thermal oxidation. This indicates effective temperature control of the extrusion and film blowing processes. Low concentrations of additives, no more than 2-3% by mass, are added to the polymer and are encapsulated in granulated polymer beads prior to melting and extrusion. This results in minimal release of these substances into the working environment. There is no evidence to suggest that significant levels of carcinogens, respiratory sensitisers or irritants are being generated in the process fume.

4.3 SITE 3 – PE AND RECYCLED PE EXTRUSION, BLOWN FILM AND WELDING


The company manufacture polyethylene bags using some recycled polymer in a blown film extrusion process similar to site 2.

The extrusion hall comprised of 12 extruders, 9 of these have the capability to apply text using water-based inks. The printable lines are all located on one side, with the non-printable lines opposite. The site typically extrudes 70 tonnes of material daily. The company produce the bags in a batch process. Raw materials are delivered in granular form in 1 tonne quantities in fibreboard containers. The containers are taken to the rear of the extruders and a feed pipe is inserted. Chalk is added as a filler. The process involves typical blown film extrusion where the raw materials are heated to around 180 OC and mixed by a rotary screw mechanism and extruded and blown out into a thin cylindrical film. This is then air cooled and passed through a series of rollers, cutters and a welder to produce the finished bags that are stored on a large roll.


There is a forced mechanical general ventilation system in the extrusion hall. There is no LEV in place. RPE is not worn for general production tasks.

4.3.3 Main findings

• Total inhalable particulate levels were in the range <0.05 - 0.15 mg/m3.

• No evidence of exposure to toxic metals was found (all <0. 01 mg/m3).

• Low levels of formaldehyde (0.2–1.7 µg/m3) were detected. These are 3 to 4 orders of magnitude lower than the WEL of 2.5 mg/m3.

• Several solvents (all <0.5ppm) were identified which may have originated from cleaning or other processes carried out in other areas of the plant.

• The concentrations of aldehydes, VOCs and other semi-volatile materials were generally several orders of magnitude below any exiting WEL. 1,3-Dichlorobenzene

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was also identified (< 0.5 ppm) although its origin could not be identified. A range of PAHs were also detected at very low levels (<1ng/m3) a number of these described as carcinogens; benzo(a)pyrene (IARC category 1), dibenz(a,h)anthracene (IARC 2A), benzo(b)fluoranthene, benzo(k)fluoranthene and naphthalene (IARC 2B) although occurring at levels too low to be of concern and may or may not arise from the process fume.


The low levels of oxygenated compounds such as aldehydes, ketones and alcohols indicate the low level of polymer degradation through thermal oxidation suggesting effective temperature control of the extrusion and film blowing processes. Several carcinogenic PAHs were detected at very low levels (<1ng/m3). No significant levels of carcinogens, respiratory sensitisers or irritants were detected in the air samples at sufficient levels to be of concern.

4.4 SITE 4 – PE, PP, PS RECYCLING AND EXTRUSION


The company recycle used plastics to form pelletised material for resale. Waste material is cleaned, sorted and shredded prior to extrusion. Five of the six extrusion lines were running on the day of the visit which were processing high impact polystyrene, polypropylene (3 extruders), high density polyethylene and polypropylene. Recycled plastics are purchased in bales that are sorted, cleaned, shredded and stored in silos for use as raw material for extrusion into pellet. The shredded plastics are transported by piping into the extrusion hall and fed into the barrel of the extruder where they are mixed at 180 OC. Moisture and volatile compounds are removed under vacuum. The blended mixture is extruded through a die plate into pellets that are quenched in water, dried and fed to a bagging plant in the adjacent storage area.


There are three roof-mounted fans within the extrusion hall that provide increased air movement. LEV is fitted to the screen changing units. RPE was available for various cleaning tasks.

4.4.3 Main findings

• Total inhalable particulate levels were in the range 0.44 - 1.03 mg/m3.


• Low levels of formaldehyde (3.1–7.2 µg/m3) were detected. These are 2 to 3 orders of magnitude lower than the UK WEL of 2.5 mg/m3.

• Styrene was found in all air samples (< 0.5 ppm) that could have arisen from thermal degradation of the polystyrene during extrusion.

• A wide range of hydrocarbons, VOCs and solvents were present at low levels (all < 0.5 ppm).

• The concentrations of aldehydes, VOCs and other organic compounds were typically at least 1-2 orders of magnitude lower than any respective WELs. A range of PAHs were also detected at very low levels (<1ng/m3) a number of these described as carcinogens; benzo(a)pyrene (IARC category 1), dibenz(a,h)anthracene (IARC 2A),

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benzo(b)fluoranthene, benzo(k)fluoranthene and naphthalene (IARC 2B) although occurring at levels too low to be of concern.


The general low levels of VOCs present demonstrate effective temperature control of the extrusion process and the absence of significant polymer degradation. A wide range of VOCs were detected at low levels which may not all be attributable to the extrusion process. A range of other activities such as raw material preparation and cleaning operations were conducted in areas adjacent to the extrusion lines. The VOCs may originate from contaminants on the recycled material in use and may account for the strong odour at the site. No significant levels of carcinogens, respiratory sensitisers or irritants were detected in the air samples at levels thought to be of concern.

4.5 SITE 5 – PET EXTRUSION AND BLOW INJECTION MOULDING


The site manufactures a variety of small to medium sized plastic items, such as food and drink containers, primarily from PET using injection blow moulding. Pellets of virgin PET are brought onto site by road tanker, and offloaded into storage silos. From here it is hard piped using a sealed transfer system to the injection blow moulding machines. The pellets are fed through a desiccating chamber to remove moisture. It is then fed from a storage silo into the barrel of the extruder and heated to 280°C. The molten PET passes from the screw into a mould. There are several moulds, mounted on a carousel, on the machine. These are located within a safety enclosure. The moulds travel around the carousel where metal rods are inserted and the final item is ‘blown’ into shape using compressed air. The moulded items are transferred onto a conveyor belt, which takes them to a packing area. The moulded items cool rapidly, and by the time they leave the safety enclosure around the carousel they are only slightly above room temperature.


There are a large number of roof fans (extracting) and air handling units (blowing inward) in the roof space, providing a high degree of air movement in the workroom. No LEV is applied to the injection blow moulding process. RPE is not worn in the PET injection blow moulding area during routine operation.

4.5.3 Main findings



• Very low levels of formaldehyde and other aldehydes (<0.1 µg/m3) were found.

• Very low levels of VOCs were found (all < 32 ppb).

• The concentrations of aldehydes, VOCs and other organic compounds were typically at least 3 orders of magnitude lower than any respective WEL . Naphthalene (IARC 2B) and a range of non-carcinogenic PAHs were also detected at very low levels (all <1ng/m3).

13


The background levels of all analytes were exceedingly low at this site demonstrating the low levels of emissions generated from this process and effective temperature control of the extrusion and blow moulding activities.

4.6 SITE 6 – ABS VACUUM FORMING OF SHEET


The site manufactures various items such as car roof boxes, caravan panels etc, primarily from ABS and HDPE using vacuum forming techniques. The visit focussed on processes involving ABS as sufficient information on PE had already been gathered. The acrylic capped (removable thin coat) ABS sheets used to form a caravan panel was manually loaded onto a large carousel. This is then rotated round to the heating oven position. The temperature and duration of heating period is dependent on the type of product being produced. The typical processing temperature was 160 –180 oC. From the oven the softened sheet is rotated to the heated mould onto which it is lowered and vacuum applied. After approximately 30 seconds an array of cooling fans situated around the mould are switched on for 3 minutes. The cast is finally rotated around to the loading/unloading area and transferred by two operators to the trimming area where air tools, or band saw are used. From here the moulded sheets are transferred to the CNC cutting area.


There is an extensive general ventilation system to aid cooling within the production area given that large amounts of heat are generated. No LEV is installed on the vacuum forming machines. RPE is not worn during normal operation.

4.6.3 Main findings



• Very low levels of formaldehyde and other aldehydes (<0.1 µg/m3) were found.


• The concentrations of aldehydes, VOCs and other organic compounds were typically at least 3 orders of magnitude lower than their respective WEL. Analytes of particular interest such as butadiene, acrylonitrile and styrene that would clearly demonstrate polymer degradation were absent from the air samples. Naphthalene (IARC 2B) and a range of non-carcinogenic PAHs were detected at very low levels (all <1ng/m3).


The background levels of all analytes were exceedingly low which demonstrates the low emissions generated and effective temperature control of the vacuum forming process. The monitoring data suggests a very low risk from carcinogens, respiratory sensitisers and irritants.

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4.7 SITE 7 – PVC EXTRUSION


The company manufacture pipes for use in various applications such as gas and water mains. This is made using a continuous extrusion processes. The majority of the pipe is manufactured from polyethylene and a smaller proportion from PVC. The visit focussed on the processes involving PVC as sufficient information on PE had already been gathered.

The bulk PVC pellet is stored in external silos and is hard piped to the mixing area. The additives (pigments etc.) are stored within the main building. These are added in a separate area, located on a mezzanine floor, away from the main extrusion hall. Additives are weighed in a ventilated cabinet then mixed into the PVC in an automated mixer. From here, the raw materials (PVC plus additives) are hard piped to the extrusion line, where they are fed into the extruder via a continuous, automated sealed transfer system. Within the extruder the raw ingredients pass through a heated screw that is maintained between 180°C and 200oC and through a die which forms the profile of the pipe. The pipe then passes through a vacuum oven, approximately 6 metres long then into two sequential enclosed cooling baths, each around 6 metres long.

Between the vacuum oven and the cooling baths, a section of the pipe, which is still warm after leaving the cooling oven, is open to the workroom atmosphere as it moves along the line. After leaving the cooling baths, the pipe is cut to length using an automated saw then stacked automatically. Under normal operating conditions the line requires very little manual operator intervention.

On the day of the visit the PVC extrusion line was experiencing technical problems. This resulted in a section of the enclosure adjacent to the extruder dye being removed and hot product, visibly fuming as it left the extruder, being open to the workroom atmosphere. This was manually cut from the line using a hand held knife and discarded onto the floor adjacent to the extruder where it was left to cool. The cooled material was collected and sent for rework. The line was operated in this manner for around 90 minutes at the beginning of the sampling period. Airborne emissions to the workroom atmosphere from the process would have been significantly higher during this period than during normal operation. Discussion with the line operators indicated that such breakdowns were infrequent.


The transfer of material to the extruder, the heated screw, extrusion dye and vacuum oven are totally enclosed under normal operation. The vacuum oven is maintained under negative pressure by a vacuum pump. It was not clear where the exhaust of this pump vented, but it appeared likely that it could have been venting within the workroom. The cooling baths are totally enclosed. No RPE is worn for normal operations on the PVC extrusion area.

4.7.3 Main findings



• Low levels of formaldehyde and other aldehydes were found (<0.1 µg/m3).

• Very low levels of HCl (0.0011 – 0.0023 mg/m3) and VCM (<0.01 ppb) were consistent with low levels of polymer degradation.

15


• The concentrations of aldehydes, VOCs and other organic compounds were typically at least 3 orders of magnitude lower than any respective WELs. VCM and HCl levels were consistent with a lack of polymer degradation. Naphthalene at 100 ng/m3 (IARC 2B) and a range of non-carcinogenic PAHs were also detected at low concentrations (all <10ng/m3).


The background levels of all analytes were exceedingly low indicating the low emissions generated and effective temperature control of the extrusion processes. The monitoring data suggests a very low risk from carcinogens, respiratory sensitisers and irritants.

4.8 SITE 8 – EPS BLOW MOULDING AND HOT WIRE CUTTING


The site manufactures insulation products for the construction industry, using expanded polystyrene. Large polystyrene blocks (approximately 7.4 m x 1.5m x 1.5 m) are produced on site at

different densities, depending on the application of the final product, by the expansion of polystyrene beads using pentane as a blowing agent under gentle heating. The block manufacture takes place adjacent to the cutting lines, but in a dedicated area. Once blown the blocks are stored on site in dedicated warehousing facilities. The blocks are taken from the warehouse into the cutting hall where they are lowered onto one of two automated cutting lines. As the block moves down the line it undergoes a series of cuts in both horizontal and vertical planes by oscillating hot wires heated to around 200 oC. A final cut to produce the required length is made by hot wires mounted in a movable frame. Off-cuts are recovered under suction and returned to the block production area for recycling.


Forced mechanical dilution ventilation is installed in the main workroom. No LEV is used, RPE is not worn for normal production activity.

4.8.3 Main findings


• No evidence of exposure to toxic metals was found (all <0. 01 mg/m3).

• Low levels of formaldehyde (5 – 9 µg/m3) and other aldehydes including benzaldehyde and acetophenone were found (<5 - 9 µg/m3).

• Very low levels of aromatic compounds such as benzene (0.3 – 0.7 ppb, R45, IARC 1), styrene (23 – 84 ppb), toluene (0.8 – 1.6 ppb) and ethylbenzene (9 – 20 ppb) were found.

• N-Pentane (3–5.2 ppm) and methylbutane (1.2 – 2.6 ppm) were the predominant VOCs that originated from the blowing agent.

• The concentrations of aldehydes, styrene, benzene, VOCs and other organic compounds were typically at least 3 orders of magnitude lower than their respective WEL.

16

Naphthalene (< 50 ng/m3, IARC 2B) and a range of non-carcinogenic PAHs were also detected at very low levels. (<10 ng/m3).


Apart from the blowing agent, n-pentane and methyl butane, background concentrations of aldehydes, aromatic hydrocarbons and VOCs were very low. It is possible that these compounds originate from the blow moulding and/or the hot wire cutting. The temperature of the hot wires was well controlled to reduce the fume emitted although some fume was still visible and was dispersed by the general ventilation. Slightly higher levels of aromatic compounds and PAHs were found compared to most of the other sites which may reflect the type of material in use however other than naphthalene none of the PAHs were classified as carcinogenic. Overall the monitoring data suggests a very low risk from carcinogens, respiratory sensitisers and irritants.

4.9 SITE 9 - PVC/CHLORINATED PVC ALLOY THERMOFORMING


The site manufactures a range of products by vacuum thermoforming of PVC sheet. Single sheets of the PVC alloy were loaded into the vacuum thermoforming machine where it was heated to approximately 180 oC. The mould is raised up such that it comes into contact with the sheet and a vacuum is then applied to complete the forming process. The heat and vacuum are applied for a predetermined length of time usually a few minutes. The moulded product is then cooled by fans and removed from the machine manually and transferred to the trimming and finishing area.


Forced mechanical dilution ventilation is present. Together with cooling fans on the thermoforming machines this provided good air movement. No LEV was used, RPE was not worn for normal production activity.

4.9.3 Main findings

• Total inhalable particulate results were all <0.1 mg/m3.


3• Low levels of formaldehyde (<0.1–2 µg/m3) and other aldehydes (all <0.1 µg/m ) were found.

• HCl (<0.001 mg/m3) and VCM (<0.01 ppb) were consistent with low levels of polymer degradation.

• Very low levels of VOCs (all < 190 ppb) were found.

• The concentrations of aldehydes, VOCs and other organic compounds were typically at least 3 orders of magnitude lower than any respective WEL. VCM and HCl levels were evidence of the lack of significant polymer degradation. A range of PAHs including naphthalene (20 ng/m3, IARC 2B) and a range of non-carcinogenic PAHs (all <20 ng/m3) were detected.

17


The background levels of all analytes were exceedingly low which demonstrates the low emissions generated and effective temperature control of the thermoforming processes. The monitoring data suggests a very low risk from carcinogens, respiratory sensitisers and irritants.

4.10 SITE 10 – PVC WELDING


The company manufactures a range of u-PVC plastic products, primarily door frames. The u-PVC profiled components are manually loaded into a welding machine. With the exception of the unloading stage, the rest of the welding process is automated although the operator will stay in close proximity. Heated plates are lowered onto the faces of the u-PVC components that are to be welded together for about 45 seconds. The plate temperature is controlled to 245 oC. The plates are then retracted and the two components are automatically mated to allow the two parts to weld. The time period allowed for the welding of the two components to take place is 35 seconds. The welded component can then be unloaded. Each machine can perform two welds simultaneously so the manufacture of a complete door- frame from the four individual components will require two weld cycles. Once complete the four welds on each door- frame are machined automatically which improves the appearance of the weld.


No forced mechanical dilution ventilation is installed. No LEV was in use, RPE was not worn for normal production activity.

4.10.3 Main findings

• Total inhalable particulate levels were in the range < 0.02 – 0.17 mg/m3.


• Low levels of formaldehyde were found (<0.1 µg/m3) and an absence of other aldehydes.

• HCl (0.0046 – 0.0054 mg/m3) and VCM (<0.01 ppb) were consistent with low levels of polymer degradation.

• Other than dichloromethane (2.3–3.7 ppm, WEL 100 ppm) low levels of VOCs (all < 340 ppb) were found.

• The concentrations of aldehydes, VOCs, solvents and other organic compounds were typically at least 1- 3 orders of magnitude lower than their respective WEL . VCM and HCl levels were evidence of the lack of significant polymer degradation. A range of PAHs was also detected. Other than naphthalene,(60 ng/m3, IARC 2B) all others compounds (all < 20 ng/m3) are considered to be non-carcinogenic.


The background levels of all analytes were exceedingly low which demonstrates the low emissions generated and effective temperature control of the welding processes. Dichloromethane (R40) was the most predominant VOC that originated from a lamination

18

process adjacent to the welding operation. The monitoring data suggests a very low risk from carcinogens, respiratory sensitisers and irritants.

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5 DISCUSSION

5.1 MATERIALS AND PROCESSES INVESTIGATED

The majority of the thermo-polymers and thermoforming processes initially identified by the stakeholders were studied during the scope of this project. Several of the sites processed other polymers in addition to the one studied during the site visit. PP and high and low density PE were the most commonly encountered polymers.

Amongst the sites visited, the perception was that the fume generated from thermal processing of plastics was, under normal operating conditions, of relatively low toxicity. None of the sites perceived significant potential for exposure to carcinogens or respiratory sensitisers from their operations.

The only widely used polymer not encountered in the survey was PMMA. PMMA is known to thermally degrade to its monomer when treated at excessive temperatures (Gao Z et al., 2004). There is also a lack of evidence in the literature to support concerns over the release of carcinogens or respiratory sensitisers from this material when processed. Evidence from laser cutting of PMMA (Sims et al., 1993) also suggests that thermal breakdown products are of low toxicity.

Evidence in the literature (Sims et al., 1993) suggested that laser cutting would be a process that had the greatest potential to generate substantial quantities of harmful substances, particularly from PVC. The view of the Association of Industrial Laser Users (AILU), with regard to best practice to safely laser cut plastics is clear, and recommends a high level of control or containment (Roberts, 2005). AILU promote in their guidance to their association that because of the high standard of controls required and the potential health risks from the fume, laser cutting has limited use for plastics. It also advises against cutting PVC because it has the greatest potential to release harmful substances (Green M and Powell J, 1999). AILU confirmed that small job shops avoid laser cutting of plastics because of high level of controls required compared to the cutting of steel but suggested that PMMA was the most likely material to be cut because of the low risk associated with the fume.

5.2 AIR MONITORING RESULTS

At the majority of sites it was not possible to clearly separate background environmental levels of contaminants, those generated from other procedures carried out at the site and those generated from the thermoforming activity of interest due to the low concentrations found.

The carcinogens detected during the site visits are summarised in Table 4. Respiratory sensitisers are not included in Table 4 since none were detected at any site.

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5.3

Table 4. Summary of carcinogens detected.

Site reference Process studied Carcinogens detected 1 PVC

compounding Vinyl chloride monomer (max concentration 20 ppb, UK WEL 3 ppm) PAH at typical environmental concentrations

2 PE/PP extrusion Formaldehyde (max concentration 3.4 µg/m3, UK WEL 2.5 mg/m3) PAH at typical environmental concentrations

3 PE and recycled PE extrusion, blown film, welding

Formaldehyde (max concentration 1.7 µg/m3 , UK WEL 2.5 mg/m3) PAH at typical environmental concentrations

4 PE, PP, PS recycling and extrusion

Formaldehyde (max concentration 7.2 µg/m3, UK WEL 2.5 mg/m3) PAH at typical environmental concentrations

5 PET extrusion and injection blow moulding

PAH at typical environmental concentrations

6 ABS vacuum forming

PAH at typical environmental concentrations

7 PVC extrusion PAH at typical environmental concentrations 8 EPS blow

moulding and hot wire cutting

Formaldehyde (max concentration 9 µg/m3 , UK WEL 2.5 mg/m3) PAH at typical environmental concentrations

9 PVC thermoforming

Formaldehyde (max concentration 2 µg/m3 , UK WEL 2.5 mg/m3) PAH at typical environmental concentrations

10 PVC welding PAH at typical environmental concentrations

EXPOSURE CONTROL STRATEGIES

The principal exposure control employed by most sites was careful temperature control of the thermoforming process. Although the main drivers for effective temperature control are process considerations, i.e overheating plastics during thermoforming will result in scorching, which is not acceptable in the finished product. However there are clear benefits in terms of exposure control. The results of this project strongly suggest that temperature control is sufficient to prevent the generation of highly toxic thermal decomposition products.

Most sites did have forced mechanical ventilation (dilution) in the areas where thermoforming was performed. This appeared effective in controlling the low levels of fume that were generated from the thermoforming processes. At almost all sites the processes were largely automated, with very little operator intervention required under normal conditions. This provides an additional level of exposure control.

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The application of LEV to plastics thermoforming operations was not common at the sites visited. None of the sites used RPE as an exposure control during normal production activities.

It is clear that the existing guidance within Controlling fume during plastics processing, Plastics processing sheet no 13 (HSE, 2002) is valid and that well maintained plant and following the recommended processing parameters such as temperature and residence or dwell time will deliver adequate control of process fume. As the processes investigated in this work are equally prevalent in SME’s, as well as larger businesses, then this guidance equally applied to them.

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6 CONCLUSIONS

6.1 MAIN FINDINGS FROM THE MEASUREMENT SURVEY

6.1.1 Carcinogens

• The levels of carcinogens detected in the process fume at the sites investigated were found to be either low or not detected.

• Where low levels of carcinogens or potential respiratory sensitisers were found these were at concentrations 2 – 3 orders of magnitude below the respective WEL where one exists.

• The maximum concentrations of carcinogens found at the sites visited were: Benzene 3(R45) 11 ppb; formaldehyde (R40) 9 µg/m ; naphthalene (IARC 2B) < 100 ng/m3; and,

other carcinogenic polycyclic aromatic hydrocarbons (IARC 1, 2A and 2B) all < 10 ng/m3

• All substances detected in this study were measured at levels below 10% of their respective WEL, demonstrating the low level of process fume encountered.

• The low levels of total inhalable particulate measured (values from all sites were below 1.15 mg/m3) and the low concentration of all other substances measured, further demonstrates the low levels of fume generated and the effective temperature control of the respective thermal processing operations.

• A notable absence of monomers was found in the process fume, which is often a predictor of polymer degradation, and supports the evidence for good temperature control and minimal generation of process fume at the sites investigated.

• At the majority of sites it was not always possible to clearly separate background environmental levels of contaminants from those generated from other procedures carried out at the site and those generated from the thermal processing activity of interest due to the low concentrations found.

6.1.2 Respiratory Sensitisers and Irritants

• No known respiratory sensitisers (R42) were found at any of the sites investigated.

• Where low levels of respiratory irritants such as aldehydes, ketones and hydrochloric acid and were found these were at concentrations 2 – 3 orders of magnitude below respective WELs where one exists.

6.1.3 Adequacy of Control Measures

• The principal exposure controls employed at the sites investigated were a combination of process temperature control and forced mechanical dilution ventilation.

• Most processes at the sites investigated required very little operator intervention, which in itself reduced exposure risk.

• The use of LEV and RPE to control exposures to airborne contaminants generated by thermoforming processes was not commonplace at the sites visited.

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• The measurement results indicate that no carcinogens, respiratory sensitisers or respiratory irritants were detected at levels of concern at any of the sites visited. This indicates that the strategies employed are adequate to control the risks associated with exposure to these agents.

.

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7 REFERENCES

1. HSE (2006). Disease Reduction Programme: Cancer Project. The nature and extent of use of, and occupational exposure to, chemical carcinogens in the UK workplaces. Available from: http://www.hse.gov.uk/aboutus/meetings/iacs/acts/watch/091106/p7annex2.pdf. Accessed 26/11/08.

2. Office of Population Censuses and Surveys (1995). Occupational health decennial supplement the Registrar General’s decennial supplement for England and Wales (1995). Edited by Dever F., p. 80, HMSO.

Office for National Statistics. Occupational Mortality in England and Wales, 1991 – 2000. ISBN 978-1-85774-696-9.

3. Brown et al., (2007). The burden of occupational cancer in Britain. Results for bladder cancer, leukaemia, cancer of the lung, mesothelioma, non-melanoma skin cancer and sinonasal cancer. Available from: http://www.hse.gov.uk/research/rrpdf/rr595main.pdf. Accessed 20/01/09.

4. HSE (2002). Controlling fume during plastics processing. Plastics processing sheet no 13. HSE Books.

5. Sims J et al., (1993). Pollutants from laser cutting and hot gas welding of plastics, Ann. occup. Hyg., Vol. 39, No 1, pp. 35-53.

6. Forrest M et al., (1995). Emissions from processing thermoplastics, Ann. occup. Hyg., Vol. 37, No 6, pp. 665-672.

3. HSE (2005). Approved supply list. Information approved for the classification and labelling of substances and preparations dangerous for supply. Chemicals (Hazard Information and Packaging for Supply) Regulations 2002. Approved list L142 (8th edition), HSE Books, ISBN 07 17661385.

3. Meijster et al. (2004). Evaluating Exposures to complex mixtures of chemicals during a new production process in the plastics industry. Ann. occup. Hyg., Vol. 48, No 6, pp. 499-507.

6. UK Air Quality Archive. Available from: http://www.airquality.co.uk/archive/data/pah/PAH_Quarterly_Andersen_Data_to_2007_Q4_fin al_v2.xls. Accessed 21/11/08.

7. Unwin J (1999). Measurement of polycyclic aromatic hydrocarbons in mineral quench oils. HSL report No OMS/99/14.

8. Gao Z et al., (2004). Kinetics of thermal degradation of poly(methylmethacrylate) studied with the assistance of the fractional conversion at the maximum reaction rate. Polymer degradation and stability, Vol. 84, 3, pp 399-403.

9. Roberts D (2005), Laser fume and UK law. The Industrial Laser User, Issue 38, pp 6-7.

10. Green M and Powell J (1999). Dealing with plastics fume during laser cutting. The Industrial Laser User, Issue 15, p 12.

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11. The Nordic Expert Group for Criteria Documentation of health Risks from Chemicals (1998). Thermal degradation products of polyethylene, polypropylene, polystyrene, polyvinylchloride, polytertrafluoroethylene, in the processing of plastics. Available from: http://www.inchem.org/documents/kemi/kemi/ah1998_12.pdf. Accessed 14/01/09.

12. IARC (2009). Overall Evaluations of Carcinogenity to Humans. Lists of all agents, mixtures and exposures evaluated to date. Available from: http://monographs.iarc.fr/ENG/Classification/crthalllist.php. Accessed 15/01/09.

13 McElvenny (2007). Burden of Occupational Cancer in Great Britain. HSL Report No HSL/2007/32.

10. OH2008/LET/14. HSL Occupational Hygiene Section Site Visit Report










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8 APPENDIX 1 – ADDITIVES AND DEGRADATIONPRODUCTS

Table 1A. Some Additives used in Polyethylenes Class of additive Example Fillers Carbon black Pigments Titanium dioxide, chromic acid Flame retardants Antimony trioxide, chlorinated compounds Slip agents Fatty acid amines Blowing agents Azodicarbonamide,

4,4-oxybisbenzenesulphonohydrazide Rubbers Polyisobutylene, butyl rubber cross-linking agents Peroxides antioxidants Phenols antistatics Polyethylene glycol alkyl esters

Table 2A. Compounds Identified in Thermo-oxidation of Polyethylene at 264 – 289 oC Carbon dioxide Hexene Tetrahydrofuran Methylvinyl

ketone Butyric acid.

Water. Hexane10 Formaldehyde 2, 9,

11 Methylethylketone. Isovaleric acid.

Ethene. Heptene. Acetaldehyde 3, 9 2-Pentanone. Hydroxyvaleric acid Propene. Heptane. Propanol. 2-Hexanone. Crotonic acid. Propane. Octene. Acrolein4 2-Heptanone. Caproic acid. Cyclopropane. Octane. Butanal. Formic acid. Butyrolactone. Butene. Methanol. Isobutanal. Acetic acid. Valerolactone. Butane. Ethanol. Pentenal. Propionic acid. Hydroperoxides. Pentene. Furan. Acetone. Acrylic acid. Alkoxy radicals.

Table 3A. Compounds Identified in Thermo-oxidation of Polypropylene at Processing Temperatures Ethene. Methylpentene Methacrolein . Methylhexanal. Acetone. Propene. Methylheptene Butanal. Nonanal. Butanone. Isobutene. Methanol Methylpentanal. Ethenone. Cyclopropylethanone Pentadiene. Methylpropen-ol Octanal. 3-Buten-2-one. 3-Penten-2-one Dimethylpentene. Ethanol Decanal. 1-Hydroxy-2-

propenone. 2, 3-Butanedione

Dimethylbenzene Methylfuran Acetaldehyde 3, 9 Methyl-3-buten-2-one. 2,4-Pentanedione. Ethane. Dimethylfuran Propanal. Pentanone. Methylheptanone Propane. Formaldehyde2 Methylpropanal. Cyclopropyl-2-

propanone. Formic & Acetic acid

Butane. Acrolein4 Vinylcrotonaldehyde Methylpentanone. Propionic acid.

Data in tables 1A-3A from The Nordic Expert Group for Criteria Documentation of health Risks from Chemicals (1998).

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Table 4A. Emissions Resulting from the Laser Cutting of Plastics *

Plastic Cut assist gas

Argon Air Polycarbonate Benzene 1, 5, 11

Hexane10

Toluene8

Xylenes8

Styrene8

Phenol8

p-Cresol. Naphthalene6

Benzo-furan derivative. 2-Ethyl-1,4-dimethylbenzene. Alkanes. Dibenzo(a,h)anthracene5

Benzo(b)fluoranthene6

Benzo(e)pyrene.

Benzene 1, 5, 11

Toluene8

Xylenes8

Styrene8

Phenol8

m-Cresol. Benzo-furan derivative. Benzo(a)fluorine. Fluorene. Fluoranthene.

Polyvinylchloride 2-Chloro-1,3-butadiene6

1,4-Pentadiene. Z-3-Pentenene-1-yne. 1,5-Hexadiene. Benzene 1, 5

Methylmethacrylate7

Methylcyclohexane. Toluene8

Chlorobenzene8

Styrene8

Benzaldehyde. 1,2-Propadienylbenzene. 4-Ethylstyrene. Naphthalene6

Alkanes. Fluorene.

2-Chloro-1,3-butadiene6

Benzene 1, 5, 11

Toluene8

Styrene8

1-Propynylbenzene. 1,3-Butadienylbenzene. Naphthalene6

Alkanes. Pyrene. Benzo(a)fluorine.

Polyethylene terephthalate Benzene 1, 5, 11

Toluene8

Xylene8

Styrene8

Phenylacetylene. Benzaldehyde. Methylphenyl ketone. Alkanes. Phenanthrene. Anthanthrene.

Phenylacetylene. Benzaldehyde. Methylphenyl ketone. Phenol 8

Alkanes. Fluorene. Pyrene. Chrysene6

Benzo(a)anthracene6

Dibenz(a,h)anthracene5

Polymethyl methacrylate Methylmethacrylate7

Toluene8

Xylene8

Trimethylbenzene. Alkanes.

Methylmethacrylate7

Toluene8

Xylene8

Trimethylbenzene. Alkanes.

Epoxide-glass Toluene8

Z-2-Heptenal. Xylenes8

4-Methylcycloheptanone. Tridecanol. Trimethylbenzene. Alkanes. Anthanthrene.

Xylenes8

Tridecanols. Trimethylbenzene. Alkanes. Anthanthrene.

* Data from Sims et al., (1993).

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Table 5A. Emissions Resulting from the Hot Gas Welding of Plastics (+ 15 oC from optimum processing temperature) *

Plastic Polycarbonate Toluene8

Isobutyl acetate. Butyl acetate. Chlorobenzene8

Ethylbenzene8

Xylenes8

Alkanes.

Acetone. Chlorobenzene8

Phenol8

Alkanes. Methylcyclohexane.

Polyvinylchloride Acetone. Toluene8

3-methy-2-butanone. Xylene8

Methylcyclohexane. 2-Ethoxyethylacetate. 6-Methyl-1-heptanol. Alkanes.

Polymethy methacrylate Acetone. Hexane10

Methylmethacrylate7

Ethylbenzene 8

Xylene8

1,3-Dichlorobenzene. Alkanes.

Nylon Acetone. Hexane10

Toluene8

Ethylbenzene8

Xylene8

1,3-Dichlorobenzene. 6-Aminohexanoic acid.

Polypropylene Acetone Hexane10

Toluene8

Ethylbenzene8

Xylene8

Hexenol. 1,3-Dichlorobenzene. 4-Methyl-2-heptanone. Alkanes.

* Data from Sims et al., 1993.

Key to tables 2-5.

1 R45 (may cause cancer)2 R43 (may cause sensitisation by skin contact)3 R36/37 (irritating to eyes and respiratory system),4 R26 (very toxic by inhalation)5 IARC 2A (Carcinogenic to humans (IARC, 2009))6 IARC 2B (Probably carcinogenic to humans (IARC, 2009))7 R37/38 (irritating to the respiratory system and skin)8 R20 (harmful by inhalation)9 R40 (limited evidence of carcinogenic effect)10R48/20 (Harmful: danger of serious damage to health by prolonged exposure through inhalation11 IARC 1 (carcinogenic to humans, (IARC), 2009))

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9 APPENDIX 2 - AIR MONITORING RESULTS

Site 1- PVC Compounding and extrusion

Analyte Method reference 8-hr WEL Measured airborne concentration

Sampler A1 Sampler A2 Sampler B1 Sampler B2 Formaldehyde 1/2 2.5 mg/m3 <0.08 µg/m3 <0.08 µg/m3

Butanal 1/2 - <0.01 µg/m3 <0.01 µg/m3

Glyoxal 1/2 - <0.01 µg/m3 <0.01 µg/m3

Benzaldehyde 1/2 - <0.01 µg/m3 <0.01 µg/m3

Hexanal 1/2 - <0.01 µg/m3 <0.01 µg/m3

Pentanal 1/2 - <0.01 µg/m3 <0.01 µg/m3

Pyruvaldehyde 1/2 - <0.01 µg/m3 <0.01 µg/m3

HCl 3 2 mg/m3 0.0036 mg/m3 0.0038 mg/m3 0.0043 mg/m3 <0.002 mg/m3

TIP** 4 10 mg/m3 0.39 mg/m3 0.46 mg/m3 0.55 mg/m3 0.64 mg/m3

Azodicarbonamide 4 1.0 mg/m3 <0.04 mg/m3 <0.04 mg/m3 <0.04 mg/m3 <0.04 mg/m3

Total Chromium 5 0.5 mg/m3 <0.01 mg/m3 <0.01 mg/m3 <0.01 mg/m3 <0.01 mg/m3

Cadmium 5 0.025 mg/m3 <0.01 mg/m3 <0.01 mg/m3 <0.01 mg/m3 <0.01 mg/m3

Lead 5 0.15 mg/m3 <0.01 mg/m3 <0.01 mg/m3 <0.01 mg/m3 <0.01 mg/m3

1,2-ethanediol 6/7 - <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm nC8-nC14

hydrocarbons 6/7 - <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm

Ethylhexanol 6/7 - <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm 2,4-pentadione 6/7 - <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm 1,3 –butadiene 8 10 ppm <0.5 ppb <0.5 ppb <0.5 ppb <0.5 ppb Vinyl chloride

monomer 9/10 3 ppm 6 ppb 20 ppb 10 ppb 3 ppb

Acrylonitrile 11 2 ppm <0.01 ppb <0.01 ppb <0.01 ppb <0.01 ppb 2,4 bis(1,1-

dimethyl) phenol 12 - <1 ng/m3 <1 ng/m3

Butylated hydroxy toluene 12 10 mg/m3 <1 ng/m3 <1 ng/m3

Drometrizole 12 - <1 ng/m3 <1 ng/m3

Napthalene 12 - <1 ng/m3 <1 ng/m3

Fluorene 12 - <1 ng/m3 <1 ng/m3

Fluoranthene 12 - <1 ng/m3 <1 ng/m3

Phenanthrene 12 - <1 ng/m3 <1 ng/m3

Pyrene 12 - <1 ng/m3 <1 ng/m3

**Total Inhalable Particulate

30

Site 2- PE and PP Extrusion and blown film

Analyte Method reference 8-hr WEL

Measured airborne concentration

Sampler A1 Sampler A2 Sampler B1 Sampler B2

Formaldehyde 1/2 2.5 mg/m3 3.4 µg/m3 2.3 µg/m3

Glyoxal 1/2 - <0.01 µg/m3 <0.01 µg/m3


HCl 3 2 mg/m3 0.0028 mg/m3 0.0040 mg/m3 0.0036 mg/m3 0.0028 mg/m3

TIP 4 10 mg/m3 <0.27 mg/m3 <0.27 mg/m3 <0.27 mg/m3 0.43 mg/m3

Azodicarbonamide 4 1 mg/m3 <0.03 mg/m3 <0.03 mg/m3 <0.03 mg/m3 <0.03 mg/m3




Ethanol 6/7 1000 ppm <1.0 ppm <1.0 ppm <1.0 ppm <1.0 ppm nC10-nC14


Ethyl acetate 6/7 200 ppm <1.0 ppm <1.0 ppm <1.0 ppm <1.0 ppm Propyl acetate 6/7 200 ppm <1.0 ppm <1.0 ppm <1.0 ppm <1.0 ppm

Propylene glycol 6/7 150 ppm <1.0 ppm <1.0 ppm <1.0 ppm <1.0 ppm Methylether 6/7 400 ppm <1.0 ppm <1.0 ppm <1.0 ppm <1.0 ppm n-propanol 6/7 200 ppm <1.0 ppm <1.0 ppm <1.0 ppm <1.0 ppm

Iso-propanol 6/7 400 ppm <1.0 ppm <1.0 ppm <1.0 ppm <1.0 ppm 1,3 –butadiene 8 10 ppm <0.5 ppb <0.5 ppb <0.5 ppb <0.5 ppb Vinyl chloride

monomer 9/10 3 ppm <0.01 ppb <0.01 ppb <0.01 ppb <0.01 ppb


dimethyl) phenol 12 - <1 ng/m3 <1 ng/m3 <1 ng/m3 <1 ng/m3

nC16-nC20 hydrocarbons 12 - <1 ng/m3 <1 ng/m3 <1 ng/m3 <1 ng/m3

Tetradecanoic acid 12 - <1 ng/m3 <1 ng/m3 <1 ng/m3 <1 ng/m3

n-hexadecanoic acid 12 - <1 ng/m3 <1 ng/m3 <1 ng/m3 <1 ng/m3

Hexadecene 12 - <1 ng/m3 <1 ng/m3 <1 ng/m3 <1 ng/m3

Octadecene 12 - <1 ng/m3 <1 ng/m3 <1 ng/m3 <1 ng/m3

Naphthalene 12 - <1 ng/m3 <1 ng/m3




Pyrene 12 - <1 ng/m3 <1 ng/m3

31

Site 3- PE and recycled PE Extrusion, blown film and welding


Sampler A1 Sampler A2 Sampler B1 Sampler B2 Formaldehyde 1/2 2.5 mg/m3 1.7 µg/m3 0.2 µg/m3

Acetaldehyde 1/2 - < 0.01 µg/m3 < 0.01 µg/m3

Glyoxal 1/2 - < 0.01 µg/m3 < 0.01 µg/m3

Benzaldehyde 1/2 - < 0.01 µg/m3 < 0.01 µg/m3

Pyruvaldehyde 1/2 - < 0.01 µg/m3 < 0.01 µg/m3

HCl 3 2 mg/m3 0.0034 mg/m3 0.0030 mg/m3 0.0034 mg/m3 <0.0016 mg/m3

TIP 4 10 mg/m3 0.08 mg/m3 0.10 mg/m3 <0.05 mg/m3 0.15 mg/m3





nC10-nC14 hydrocarbons 6/7 - <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm Toluene 6/7 50 ppm <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm

Limonene 6/7 - <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm 1, 3-Dichlorobenzene 6/7 - <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm

Iso-propanol 6/7 400 ppm <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm

n-Butanol 6/7 50 ppm (STEL) <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm

Methylethyl ketone 6/7 - <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm Propylene glycol

methylether 6/7 100 ppm <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm

1,3-butadiene 8 10 ppm <0.5 ppb <0.5 ppb <0.5 ppb <0.5 ppb Vinyl chloride monomer 9/10 3 ppm <0.01 ppb <0.01 ppb <0.01 ppb <0.01 ppb

Acrylonitrile 11 2 ppm <0.01 ppb <0.01 ppb <0.01 ppb <0.01 ppb 2,4 bis(1,1-dimethylethyl)

phenol 12 - < 1 ng/m3 < 1 ng/m3

nC16-nC22 Hydrocarbons 12 - < 1 ng/m3 < 1 ng/m3

Nonylphenol 12 - < 1 ng/m3 < 1 ng/m3

Naphthalene 12 - < 1 ng/m3 < 1 ng/m3

Acenapthalene 12 - < 1 ng/m3 < 1 ng/m3

Phenanthrene 12 - < 1 ng/m3 < 1 ng/m3

Pyrene 12 - < 1 ng/m3 < 1 ng/m3

Anthracene 12 - < 1 ng/m3 < 1 ng/m3

Chrysene 12 - < 1 ng/m3 < 1 ng/m3

Benzo(b,k)fluoranthene 12 - < 1 ng/m3 < 1 ng/m3

Benzo(a)pyrene 12 - < 1 ng/m3 < 1 ng/m3

Dibenze(a,h)anthracene 12 - < 1 ng/m3 < 1 ng/m3

Benzo(g,h,i) perylene 12 - < 1 ng/m3 < 1 ng/m3

32

Site 4- PE, PP, PS Recycling and extrusion


Sampler A1 Sampler A2 Sampler B1 Sampler B2 Formaldehyde 1/2 2.5 mg/m3 3.1 µg/m3 7.2 µg/m3

Acetaldehyde 1/2 - <0.01 µg/m3 <0.01 µg/m3

Crotonaldehyde 1/2 - <0.01 µg/m3 <0.01 µg/m3

Benzaldehyde 1/2 - <0.01 µg/m3 <0.01 µg/m3


HCl 3 2 mg/m3 0.0057 mg/m3 0.0056 mg/m3 0.0015 mg/m3 0.0040 mg/m3

TIP 4 10 mg/m3 0.44 mg/m3 0.61 mg/m3 1.03 mg/m3 0.66 mg/m3





nC10-nC14 hydrocarbons 6/7 - <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm C5-C10 branched


Cyclohexane 6/7 100 ppm <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm Styrene 6/7 100 ppm <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm

Methyl cyclohexane 6/7 - <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm Xylene 6/7 50 ppm <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm

Limonene 6/7 - <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm Trimethylbenzenes 6/7 25 ppm <0.5 ppm <0.5 ppm <0.5 ppm <0.5 ppm



cyclobutanediyl) benzene 12 - <1 ng/m3 <1 ng/m3

nC16-nC22 Hydrocarbons 12 - <1 ng/m3 <1 ng/m3

n-hexanoic acid 12 - <1 ng/m3 <1 ng/m3

Napthalene 12 - <1 ng/m3 <1 ng/m3

Acenapthalene 12 - <1 ng/m3 <1 ng/m3




Chrysene 12 - <1 ng/m3 <1 ng/m3

Benzo(b,k) fluoranthene 12 - <1 ng/m3 <1 ng/m3

Benzo (a)pyrene 12 - <1 ng/m3 <1 ng/m3

Benzo(a)anthracene 12 - <1 ng/m3 <1 ng/m3

Benzo(b,k) fluoranthene 12 - <1 ng/m3 <1 ng/m3

33

Site 5- PET Extrusion and injection blow moulding Analyte Method

reference 8-hr

WEL Measured airborne concentration

Sampler A1

Sampler A2

Sampler B1

Sampler B2

Formaldehyde 1/2 2.5 mg/m3

<0.1 µg/m3 <0.1 µg/m3

Glyoxal 1/2 - <0.1 µg/m3 <0.1 µg/m3

HCl 3 2 mg/m3 0.0007 mg/m3

0.0008 mg/m3

0.0012 mg/m3

0.0010 mg/m3

TIP 4 10 mg/m3 0.16 mg/m3

0.19 mg/m3

0.08 mg/m3

0.32 mg/m3

Azodicarbonamide 4 1 mg/m3 <0.07 mg/m3

<0.07 mg/m3

<0.07 mg/m3

<0.07 mg/m3

Total Chromium 5 0.5 mg/m3

<0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

Cadmium 5 0.025 g/m3

<0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

Lead 5 0.15 g/m3 <0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

Ethanol 6/7 1000 ppm 11 ppb 6.5 ppb 1 ppb 1 ppb Isopropyl alcohol 6/7 - 32 ppb 29 ppb 3 ppb 3 ppb

Limonene 6/7 - 1 ppb 2 ppb 1 ppb 1 ppb Methyl pentane 6/7 - 32 ppb 23 ppb 5 ppb 7 ppb

1-methoxy 2-propanol 6/7 100 9 ppb 21 ppb 2 ppb 9 ppb 1-methoxy 2-propyl

acetate 6/7 50 ppm 0.3 ppb 0.8 ppb 0.6 ppb 0.5 ppb

Methylcyclohexane 6/7 - 21 ppb 8 ppb 3 ppb 5 ppb nC7 6/7 - 9 ppb 6 ppb 1 ppb 2 ppb nC9 6/7 - 0.1 ppb 0.3 ppb <0.1 ppb <0.1 ppb

nC10 6/7 - 0.4 ppb 0.4 ppb 0.1 ppb 0.1 ppb Toluene 6/7 50 0.6 ppb 0.6 ppb 0.4 ppb 0.4 ppb Xylene 6/7 50 1.4 ppb 0.7 ppb 1.5 ppb 0.4 ppb


Acrylonitrile 11 2 ppm <0.03 ppb <0.03 ppb <0.03 ppb <0.03 ppb 2,4-bis-(1,1-

dimethylethyl)phenol 12 - <1 ng/ m3 <1 ng/ m3

Naphthalene 12 - <1 ng/ m3 <1 ng/ m3

Fluorene 12 - <1 ng/ m3 <1 ng/ m3

Phenanthrene 12 - <1 ng/ m3 <1 ng/ m3

Fluoranthene 12 - <1 ng/ m3 <1 ng/ m3

Pyrene 12 - <1 ng/ m3 <1 ng/ m3

34

Site 6 – Vacuum forming of acrylic capped (coated) ABS Analyte Method

reference 8-hr WEL

Measured airborne concentration Sampler

A1 Sampler

A2 Sampler

B1 Sampler

B2 Formaldehyde 1/2 2.5

mg/m3 1.3 µg/m3 2.2 µg/m3

Butanone 1/2 600 mg/m3

<0.1 µg/m3 <0.1 µg/m3

HCl 3 2 mg/m3 0.0011 mg/m3

0.001 mg/m3

0.0006 mg/m3

0.0006 mg/m3

TIP 4 10 mg/m3

0.08 mg/m3

0.09 mg/m3

0.07 mg/m3

0.11 mg/m3


<0.07 mg/m3

<0.07 mg/m3

<0.07 mg/m3


<0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

Cadmium 5 0.025 mg/m3

<0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

Lead 5 0.15 mg/m3

<0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

Methyl pentane 6/7 - 10.9 ppb 0.2 ppb 1.5 ppb 0.31 ppb Methylmethacrylate 6/7 50 ppm 2 ppb 1 ppb 4 ppb 4 ppb

Alpha-Pinene 6/7 - 0.2 ppb 0.1 ppb 0.04 ppb 0.08 ppb nC7 6/7 - 1.4 ppb 0.1 ppb 0.2 ppb 0.1 ppb

nC10 6/7 - 0.5 ppb 0.2 ppb 0.2 ppb 0.2 ppb Toluene 6/7 50 0.4 ppb 0.3 ppb 0.4 ppb 0.2 ppb Xylene 6/7 50 2.2 ppb 0.3 ppb 1.3 ppb 0.3 ppb


Acrylonitrile 11 2 ppm <0.01 ppb <0.01 ppb <0.01 ppb <0.01 ppb 2,4-bis-(1,1-

dimethylethyl)phenol 12 - <1 ng/ m3 <1 ng/ m3

Naphthalene 12 - <1 ng/ m3 <1 ng/ m3




Pyrene 12 - <1 ng/ m3 <1 ng/ m3

35

Site 7 – Extrusion of PVC Analyte Method

Reference 8-hr


Sampler Sampler Sampler Sampler A1 A2 B1 B2


<0.1 µg/m3 <0.1 µg/m3

Butanone 1/2 600 mg/m3

<0.1 µg/m3 <0.1 µg/m3

Glyoxal 1/2 - <0.1 µg/m3 <0.1 µg/m3


HCl 3 2 mg/m3 0.0011 mg/m3

0.0018 mg/m3

0.0023 mg/m3

0.0023 mg/m3

TIP 4 10 0.23 0.23 1.15 0.58 mg/m3 mg/m3 mg/m3 mg/m3 mg/m3


<0.04 mg/m3

<0.04 mg/m3

<0.04 mg/m3

Total Chromium 5 0.5 <0.01 <0.01 <0.01 <0.01 mg/m3 mg/m3 mg/m3 mg/m3 mg/m3

Cadmium 5 0.025 <0.01 <0.01 <0.01 <0.01 mg/m3 mg/m3 mg/m3 mg/m3 mg/m3

Lead 5 0.15 <0.01 <0.01 <0.01 <0.01 mg/m3 mg/m3 mg/m3 mg/m3 mg/m3

Methyl pentane 6/7 - 38 ppb 12 ppb 25 ppb 2 ppb Methylethylketone 6/7 - 307 ppb 168 ppb 201 ppb 118 ppb

Ethylene glycol 6/7 - 2 ppb 2 ppb 16 ppb 9 ppb nC10 6/7 - 1 ppb <0.01 ppb 2 ppb 2 ppb nC11 6/7 - < 0.01 ppb <0.01 ppb 2 ppb 2 ppb nC12 6/7 - 1 ppb <0.01 ppb 2 ppb 2 ppb


Acrylonitrile 11 2 ppm <0.01 ppb <0.01 ppb <0.01 ppb <0.01 ppb 2,4-bis-(1,1- 12 - <1 ng/ m3 <1 ng/ m3

dimethylethyl)phenol Naphthalene 12 - <100 ng/ m3 <100 ng/ m3

Acenaphthalene 12 <10 ng/ m3 <10 ng/ m3

Acenaphthene 12 <10 ng/ m3 <10 ng/ m3




Pyrene 12 - <10 ng/ m3 <10 ng/ m3

36

Site 8 – EPS Blow moulding and hot wire cutting Analyte Method

Reference 8-hr




9µg/m3 5µg/m3

Benzaldehyde 1/2 - <9µg/m3 <5 µg/m3

Acetophenone 1/2 - <9µg/m3 <5µg/m3

Glyoxal 1/2 - <9µg/m3 <5µg/m3

Pyruvaldehyde 1/2 - <9µg/m3 <5µg/m3

HCl 3 2 mg/m3 <0.001mg/m3 <0.001 mg/m3

<0.001 mg/m3

<0.001mg/m3

TIP 4 10 mg/m3 0.21 mg/m3 0.21 mg/m3

0.16 mg/m3

0.11 mg/m3

Azodicarbonamide 4 1 mg/m3 <0.04 mg/m3 <0.04 mg/m3

<0.04 mg/m3

<0.04 mg/m3


<0.01 mg/m3 <0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3


<0.01 mg/m3 <0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

Lead 5 0.15 mg/m3

<0.01 mg/m3 <0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

Methyl butane 6/7 - 2609 ppb 2285 ppb 1242 ppb 1785 ppb n-Pentane 6/7 - 5244 ppb 4821 ppb 3013 ppb 3514 ppb

Cyclopentane 6/7 - 99 ppb 68 ppb 56 ppb 60 ppb Benzene 6/7 1 ppm 0.7 ppb 0.5 ppb 0.3 ppb 0.4 ppb Toluene 6/7 50 ppm 1.6 ppb 1.3 ppb 0.8 ppb 0.8 ppb

Methylformamide 6/7 - 1.9 ppb 3.5 ppb <0.01 1.4 ppb ppb

Ethyl Benzene 6/7 100 ppm 20 ppb 25 ppb 9 ppb 17 ppb Styrene 6/7 100 ppm 84 ppb 76 ppb 23 ppb 42 ppb

Alpha-pinene 6/7 - 1.1 ppb 0.6 ppb 0.7 ppb 0.4 ppb Acetophenone 6/7 - 3.5 ppb 2.3 ppb 3.5 ppb 2.8 ppb

Benzene 6/7 - 11 ppb 10 ppb 5 ppb 7 ppb Benzoic acid 6/7 - 21 ppb 56 ppb <0.01 7 ppb

ppb 1,3-butadiene 8 10 ppm <0.5 ppb <0.5 ppb <0.5 ppb <0.5 ppb Vinyl chloride 9/10 3 ppm <0.01 ppb <0.01 <0.01 <0.01 ppb

monomer ppb ppb Acrylonitrile 11 2 ppm <0.01 ppb <0.01 <0.01 <0.01 ppb

ppb ppb Naphthalene 12 - <50 ng/m3 <50 ng/m3

Acenaphthalene 12 - <10 ng/m3 <10 ng/m3

Acenaphthene 12 - <10 ng/m3 <10 ng/m3




Pyrene 12 - <10 ng/m3 <10 ng/m3

37

Site 9 – PVC/chlorinated PVC alloy Vacuum thermoforming Analyte Method

Reference 8-hr WEL

Measured airborne concentration Sampler A1

Sampler A2

Sampler B1

Sampler B2


2 µg/m3 <0.1 µg/m3

Glyoxal 1/2 - <0.1 µg/m3 <0.1 µg/m3


Acetaldehyde 1/2 - <0.1 µg/m3 <0.1 µg/m3

HCl 3 2 mg/m3 <0.001 mg/m3

<0.001 mg/m3

<0.001 mg/m3

<0.001 mg/m3

TIP 4 10 mg/m3

< 0.1 mg/m3

< 0.1 mg/m3

< 0.1 mg/m3

< 0.1 mg/m3


<0.02 mg/m3

<0.02 mg/m3

<0.02 mg/m3


<0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3


<0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

Lead 5 0.15 mg/m3

<0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

<0.01 mg/m3

Isopropyl alcohol 6/7 - 50 ppb 111 ppb 49 ppb 110 ppb Dichloromethane 6/7 100 ppm 45 ppb 149 ppb 48 ppb 143 ppb Methylmethacrylate 6/7 50 ppm 38 ppb 190 ppb 57 ppb 163 ppb 1,3-butadiene 8 10 ppm <0.5 ppb <0.5 ppb <0.5 ppb <0.5 ppb Vinyl chloride monomer 9/10 3 ppm <0.01 ppb <0.01 ppb <0.01 ppb <0.01 ppb Acrylonitrile 11 2 ppm <0.01 ppb <0.01 ppb <0.01 ppb <0.01 ppb Naphthalene 12 - 20 ng/m3 20 ng/m3




Pyrene 12 - <20 ng/m3 <20 ng/m3

38

Site 10 – Welding of PVC Analyte Method

Reference 8-hr




<0.1 µg/m3 <0.1 µg/m3

HCl 3 2 mg/m3 0.0053 mg/m3

0.0046 mg/m3

0.0049 mg/m3

0.0054 mg/m3

TIP 4 10 <0.02 0.14 0.17 0.14 mg/m3 mg/m3 mg/m3 mg/m3 mg/m3


<0.02 mg/m3

<0.02 mg/m3

<0.02 mg/m3

Total Chromium 5 0.5 <0.01 <0.01 <0.01 <0.01 mg/m3 mg/m3 mg/m3 mg/m3 mg/m3

Cadmium 5 0.025 <0.01 <0.01 <0.01 <0.01 mg/m3 mg/m3 mg/m3 mg/m3 mg/m3

Lead 5 0.15 <0.01 <0.01 <0.01 <0.01 mg/m3 mg/m3 mg/m3 mg/m3 mg/m3

nC5 6/7 - 19 ppb 282 ppb 47 ppb 299 ppb Dichloromethane 6/7 100 ppm 3683 ppb 2876 ppb 3295 ppb 2294 ppb

Methylethylketone 6/7 200 ppm 32 ppb 53 ppb 24 ppb 62 ppb nC7 6/7 - 17 ppb 278 ppb 15 ppb 340 ppb

Methylcyclohexane 6/7 - 6 ppb 112 ppb 5 ppb 146 ppb Toluene 6/7 50 ppm 8 ppb 4 ppb 7 ppb 4 ppb

n-butylacetate 6/7 200 ppm 5 ppb 13 ppb 9 ppb 8 ppb 1-Methoxy-2-propyl 6/7 - 3 ppb 2 ppb 4 ppb 2 ppb

acetate nC10 6/7 - 3 ppb 3 ppb 3 ppb 3 ppb

Butanedioic acid 6/7 - 12 ppb 6 ppb 10 ppb 6 ppb dimethylester

Pentanedioic acid 6/7 - 20 ppb 11 ppb 17 ppb 11 ppb dimethylester 1,3-butadiene 8 10 ppm <0.5 ppb <0.5 ppb <0.5 ppb <0.5 ppb

Vinyl chloride monomer 9/10 3 ppm <0.01 ppb <0.01 ppb <0.01 ppb <0.01 ppb Acrylonitrile 11 2 ppm <0.01 ppb <0.01 ppb <0.01 ppb <0.01 ppb Naphthalene 12 - 60 ng/m3 60 ng/m3




Pyrene 12 - <10 ng/m3 <10 ng/m3

39

10 APPENDIX 3 - SAMPLING AND ANALYTICAL TECHNIQUES

10.1 INTRODUCTION

A summary of the sampling and analytical methodology is given in table 13. Static sampling at 2 positions in close proximity to the process was employed as the aim was to identify the presence of carcinogens and respiratory sensitisers generated from the process rather than personal exposure. This allowed a broad array of highly sensitive screening techniques to be deployed at each position. A further, more detailed investigation could be carried out should hazardous substances be detected from the static sampling exercises. A number of specific analytes are listed in table 13 that includes vinyl chloride monomer, butadiene and acrylonitrile. Such potential analytes were identified from the literature (4, 5) as possible components in fume generated during thermal processing of the polymer.

10.2 LOW VOLUME SAMPLING

Samples were collected for approximately 2–6 hours depending on the type of analyte and sampling flow-rate (0.05 to 2 L/min). Sorbent tubes samples (0.05 L/min) collected for analysis by methods 6 – 11 were limited to approximately 2 hours collection time to avoid sample breakthrough. This allowed a morning and afternoon sample of each type to be collected. A sorbent tube (0.05 L/min) and also a treated filter sampler (1 L/min) were collected at each position for the aldehyde screen for robustness. The data for the filter sampler was reported here due to the greater sensitivity afforded by this sampling technique.

10.3 HIGH VOLUME SAMPLING

The high volume sampling system has been described elsewhere (7). The sampling train consists of a quartz filter (100 mm diameter) and a sorbent cartridge containing two polyurethane foam plugs retaining 25g of XAD2 resin. The sampling rate of 200 l/min ensures a low limit of detection (sub-ppb) for any particulate and semi-volatile materials such as polycyclic aromatic hydrocarbons (PAHs). The filter and cartridge are analysed separately to identify non-volatile and semi-volatile fractions of the air sample. The filter retains only particulate material whilst the cartridge will retain any semi-volatile material draw through the filter. This is the case for PAHs where a wide range of vapour pressures exists for the target compounds (EPA16).

10.4 ASSIGNMENT OF MEASUREMENT VALUES

The results of the analytical measurements in tables X – Y are frequently assigned less than values (<) in the table where concentrations either fell below the limit of detection of the analytical procedure or below the lowest calibration point of the method . Exhaustive calibration of analytical procedures down to the very low concentrations observed in many cases would have been technically difficult and time consuming and would not have benefited the interpretation of the data since demonstration of the low concentrations present was fit for purpose.

40

41

Tabl

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te (T

IP)

25 m

m G

F/A

filte

r, pr

e-co

nditi

oned

2

litre

s/m

inut

e (2

) TI

P –

grav

imet

ric.

Azo

dica

rbon

amid

e –

HPL

C/U

V

IOM

sam

pler

5 M

etal

s 25

mm

GLA

500

0 m

embr

ane

filte

r 2

litre

s/m

inut

e (2

) X

RF

MD

HS

91.

IOM

sam

pler

6 G

ener

al v

olat

ile o

rgan

ic c

ompo

und

(VO

C) s

cree

n –

tube

1

Aut

omat

ed th

erm

al d

esor

ptio

n (A

TD) t

ube

cont

aini

ng T

enax

sorb

ent

50 m

l/min

ute

(1*)

A

TD-G

C/M

S In

-hou

se m

etho

d O

MS-

001

7 G

ener

al V

OC

scre

en –

tube

2

ATD

tube

con

tain

ing

chro

mos

orb

106

sorb

ent

50 m

l/min

ute

(1*)

A

TD-G

C/M

S In

-hou

se m

etho

d O

MS-

001

8 B

utad

iene

A

TD tu

be c

onta

inin

g C

arbo

pack

X s

orbe

nt

50 m

l/min

ute

(1*)

A

TD-G

C/F

ID

In-h

ouse

met

hod

OM

S-00

1

9 V

inyl

chl

orid

e m

onom

er (V

CM

) and

lo

w m

olec

ular

wei

ght h

ydro

carb

ons

ATD

tube

con

tain

ing

PFC

sorb

ent

50 m

l/min

ute

(1*)

A

TD-G

C/M

S In

-hou

se m

etho

d O

MS-

001

10

VC

M tu

be 2

A

TD tu

be c

onta

inin

g ai

r tox

ics s

orbe

nt

50 m

l/min

ute

(1*)

A

TD-G

C/M

S In

-hou

se m

etho

d O

MS-

001

11

Acr

ylon

itrile

A

TD tu

be c

onta

inin

g TA

UC

sorb

ent

50 m

l/min

ute

(1*)

A

TD-G

C/F

ID

In-h

ouse

met

hod

OM

S-00

1

12

Sem

i vol

atile

s to

incl

ude

poly

cycl

ic a

rom

atic

hyd

roca

rbon

s (P

AH

s) C

100

mm

qua

rtz fi

lter b

acke

d up

with

2 x

Po

lyur

etha

ne F

oam

(PU

F) s

ampl

ers w

ith

XA

D s

orbe

nt b

ed in

bet

wee

n.

200

litre

s/m

inut

e (1

*)

GC

/MS

And

erso

n In

stru

men

ts

PS-1

hig

h vo

lum

e PU

F sa

mpl

er

A R

efer

ence

num

ber

for

sam

plin

g an

d an

alys

is m

etho

d em

ploy

ed. B

V

alue

s in

bra

cket

s =

num

ber

of s

ampl

e re

plic

ates

at

each

pos

ition

, * s

ampl

er

repl

aced

afte

r app

roxi

mat

ely

2 ho

urs (

mor

ning

and

afte

rnoo

n sa

mpl

es c

olle

cted

). CU

S EP

A li

st o

f 16

poly

cycl

ic a

rom

atic

hyd

roca

rbon

s com

poun

ds.

Published by the Health and Safety Executive 05/10





The report describes the results of sampling for carcinogens and respiratory sensitisers at ten large processing plants. The measurement strategy used was sufficiently broad in scope to take into account the presence of respiratory sensitisers and respiratory irritants as well as carcinogens. The findings demonstrate that compliance with HSE guidance achieves adequate prevention and control of exposure in the common thermoplastic processes considered. This report will be helpful to smaller plants operated by small and medium enterprises who undertake the same processes albeit on a smaller scale.

This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the author alone and do not necessarily reflect HSE policy.

RR797

www.hse.gov.uk

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