RR525 - Use of chemical protective gloves to control ... · gloves are used in the workplace and...

Health and Safety Executive

Use of chemical protective gloves to control dermal exposures in the uv lithographic printing subsector

Prepared by the Health and Safety Laboratory for the Health and Safety Executive 2007

RR525 Research Report

Health and Safety Executive

Use of chemical protective gloves to control dermal exposures in the uv lithographic printing subsector

Martin Roff Health and Safety Laboratory Harpur Hill Buxton Derbyshire SK17 9JN

The printing industry is one of the largest sectors in the UK. The chemicals and solvents used in the printing sector are known to cause dermatitis. This project was designed to identify the most appropriate chemical protective glove for each work activity in this sector, and review the way each work activity is carried out to try to reduce exposure risk.

Solvent chemical mixtures and chemical protective glove materials were identified in the lithographic printing industry, and workplace visits showed how the gloves were used. The printers maintained a high standard of cleanliness with the inks, however they did not appear to regard the solvents as skin hazards. There were no current cases of dermatitis.

Nitrile gloves of 0.4mm thickness (already in use) were found to resist permeation by the greatest proportion of the solvents, tested on specific chemical products. These gloves are recommended as an initial (default) choice for general use in lithographic printing. Particularly aggressive chemicals may require thicker, or different types of, gloves.

This information has been used to produce specific taskbased guidance for COSHH Essentials for Printers.

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.

HSE Books

© Crown copyright 2007

First published 2007

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, 216 Colegate, Norwich NR3 1BQ

or by email to [email protected]

ii

ACKNOWLEDGEMENTS

The author would like to especially thank the management and staff at the two printing firms, who cooperated enthusiastically during the site visits.

The author would also like to thank and acknowledge the assistance of:

John McAlinden, HSE Occupational Hygiene Specialist Inspector for supplying the comments on the occupational hygiene practices observed at the two sites.

Matthew Coldwell (HSL Organic Measurement Section) for organising and assisting with site measurements.

ABC Chemicals and Varn Chemicals who supplied solvents free of charge, and described the lithographic solvents market.

Kaechele-Cama Latex GmbH, who carried out glove permeation tests under sub-contract and gave permission for extracts and photographs to be included in this report.

Duncan Rimmer (HSL Organic Measurement Section) who organised the startup support project and specified the subcontract tender and main project.

Nick Vaughan (HSL Personal Protective Equipment Section) who provided advice on glove selection.

Other HSL staff and analysts who assisted with the field visits as part of this project: Neil Plant, Kate Gostlow and Glen McConacchie (HSL Organic Measurement Section); John Cocker, Kate Jones and Peter Akrill (HSL Biological Monitoring Section), Peter Baldwin and Chris Keen (HSL Occupational Hygiene Section); Dave Dobb and Dave Woolley (HSL Visual Presentation Section).

iii

CONTENTS

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

1.1 Dermatitis in the Printing sector ............................................................... 1

1.2 Aims of this work ..................................................................................... 1

1.2.1 HSC Strategy ........................................................................................................... 1

1.2.2 Guidance for printers currently available ................................................................ 1

1.2.3 Aims ........................................................................................................................ 2

1.3 Printing Industry Sub-sectors................................................................... 3

1.4 Objectives of this study............................................................................ 3

1.5 Stakeholders in this study........................................................................ 4

1.6 Method summary..................................................................................... 4

2 INITIAL SITE VISITS .................................................................................. 6

2.1.1 Sampling and analytical methods ............................................................................ 6

2.1.2 Company A (initial site visits of 22/10/03 and 19/11/03) ....................................... 6

2.1.3 Company B (initial site visit of 06/11/03) ............................................................... 8

3 CHEMICAL SOLVENTS USED IN THE LITHOGRAPHIC PRINTING

SECTOR .......................................................................................................... 10

3.1 ABC Chemicals ..................................................................................... 10

3.2 Varn Products........................................................................................ 10

3.3 Chemicals selected for laboratory tests ................................................. 10

4 LABORATORY GLOVE TESTING SUBCONTRACT SPECIFICATION

AND RESULTS................................................................................................ 13

4.1 Tender Specification .............................................................................. 13

4.2 Tender ................................................................................................... 13

4.2.1 Breakthrough (Permeation) Chemical Tests.......................................................... 13

4.2.2 Physical Tests ........................................................................................................ 13

4.3 Extension to the contract ....................................................................... 14

4.4 Glove performance – selection criteria .................................................. 14

4.5 Brief descriptions of the glove tests ....................................................... 16


4.5.2 Physical Tests ........................................................................................................ 17

4.6 Glove Test Results ................................................................................ 18


4.6.2 Physical Tests ........................................................................................................ 20

5 MAIN SITE VISITS.................................................................................... 25

5.1 Main sampling visit to Company B (21/9/04) ......................................... 25

5.2 First sampling visit to Company A (18/6/04) .......................................... 26

5.3 Occupational Hygiene evaluation during first visits: good practice ........ 27

5.4 Occupational Hygiene evaluation during first visits: “less good” practice28

6 LABORATORY VOLUNTEER STUDY..................................................... 29

7 FINAL SITE VISITS .................................................................................. 31

v

7.1 Return visit to Company A 21/4/05 and 22/4/05 .................................... 31

8 DISCUSSION............................................................................................ 34

8.1 Suitable Gloves ..................................................................................... 34

8.2 Permeation testing................................................................................. 34

8.2.1 Comparison of test houses..................................................................................... 34

8.2.2 Proportion of chemical in a mixture ...................................................................... 35

8.2.3 Volatility................................................................................................................ 36

8.2.4 End-point ............................................................................................................... 37

8.3 Puncture tests........................................................................................ 37

8.4 Durability................................................................................................ 37

8.5 Biological Monitoring.............................................................................. 37

8.5.1 PGME and DPGME .............................................................................................. 37

8.5.2 TMB ...................................................................................................................... 38

9 CONCLUSIONS........................................................................................ 39

9.1 Outcomes of the project......................................................................... 39

9.2 Linked further work ................................................................................ 40

9.3 Recommendations................................................................................. 40

10 REFERENCES ...................................................................................... 41

11 APPENDICES ....................................................................................... 43

11.1 APPENDIX 1 Consent form for Biological Monitoring .......................... 43

11.2 APPENDIX 2 Analysis of solvents found in use on-site ....................... 44

11.3 APPENDIX 3 Tables of Glove Puncture Resistances.......................... 47

11.4 APPENDIX 4 Initial on-site measurements at Company A .................. 48

11.5 APPENDIX 5 On-site measurements at Company B........................... 49

11.6 APPENDIX 6 On-site measurements at Company A........................... 50

vi

EXECUTIVE SUMMARY

The printing industry is one of the largest sectors in the UK. The chemicals and solvents used in the printing sector are known to cause dermatitis. The project reported here is part of the campaign to reduce dermatitis in the printing sector under the Disease Reduction Programme, part of The Health and Safety Commission’s strategy to reduce working days lost to occupational ill-health by 20% by 2010 (HSC, 2004).

Objectives

To form a partnership with stakeholders in the lithographic printing industry. To identify the chemical mixtures and chemical protective glove materials used by the stakeholders and observe how the stakeholders normally carry out the specified work activities. To observe how the gloves are used in the workplace and measure their effectiveness through biological monitoring.

To obtain quantitative laboratory test data on the permeation of specific printing industry chemical mixtures through a range of chemical protective glove materials commercially available for use by the printing industry.

To determine from the recorded data whether there is a relationship between predicted (laboratory measured) glove permeability and actual glove permeability as shown by dermal uptake of the chemicals in mixtures, and to develop task-based guidance on appropriate chemical protective glove selection for specific work activities.

To identify the most appropriate chemical protective glove for each work activity in this sector, and review the way each work activity is carried out to try to reduce exposure risk. This information will be used to produce specific task-based guidance for COSHH Essentials for Printers.

To revisit the sites to put changes into effect and monitor exposure for improvement.

Main Findings

The two initial site visits identified chemicals used by UV-lithographic printers, a specialism within the lithographic sub-sector. Other market leaders for the rest of the lithographic sub-sector were identified and a shortlist of nine selected for glove testing. Seven models of gloves, of various makes and materials all of similar durability and cost to the gloves in use on-site, were tested for permeation by a subcontractor against the nine chemicals. Nitrile gloves of 0.4mm thickness (already in use) were found to resist permeation by the greatest proportion of the chemicals tested. One solvent used during ink-mixing was found to present the greatest challenge, and no glove tested would last for a full day. A disposable glove of 0.2mm thickness resisted permeation for an hour in laboratory tests and was suggested as a single use disposable glove for the (ten minute) task.

Follow up visits using underglove measurements confirmed that the 0.2mm gloves did not permit the problem chemical to permeate in measurable quantity during single tasks with gloves sealed around the cuffs to prevent ingress. Underglove measurements with unsealed 0.4mm gloves for more general cleaning tasks showed small amounts inside the gloves on the first day, i.e. within the permeation time, but higher levels on the second day, indicating either that the chemical was now permeating the glove, or that repeated donning and doffing transferred the chemical inside (or both).

vii

Urine samples revealed three possible markers for the solvents in use. Measurements showed uptake levels just above background for the ink mixing chemical and implied that the source was inhalation rather than dermal. Another urinary marker revealed that workplace uptake of trimethylbenzene was at a level equivalent to uptake from four hours inhalation exposure to the Workplace Exposure Limit of 25ppm. Airborne levels of half the WEL were measured at the workplace. Other workers exposed to the same workplace air but not engaged in the same task showed much lower uptake, suggesting that the dermal route had been significant.

The printers maintained a high standard of cleanliness with the inks, with only the occasional lapse that could have led to short term dermal exposure. There were no current cases of dermatitis. However they did not appear to regard the solvents as skin hazards. The solvents were found in their urine, which caused them concern.

The return visits to the site revealed improved workplace cleanliness, which may be attributed to knowledge that HSE was about to attend, although this was not a formal workplace inspection. Hazard awareness to the solvents had improved, especially through use of biological monitoring.

Their previous choice of gloves for other tasks was shown to be correct, whilst glove selection was improved for the ink mixing task.

Recommendations

• Nitrile gloves of 0.4mm thickness are recommended for general use in Roller and Plate cleaning in UV lithographic printing, a recommendation based on tests with the chemical solvents that were found at the premises.

• Nitrile gloves of 0.4mm thickness are also recommended as an initial (default) choice for general use in lithographic printing, a recommendation based on tests with the market-leading solvents and washes from the rest of the lithographic printing industry. It is acknowledged that it has not been possible to make a comprehensive survey of all chemicals in this study, and that particularly aggressive chemicals may require a different type of glove.

• Nitrile gloves of 0.4mm thickness are not recommended for ink mixing using 1-methoxy-2-propanol for a full shift, even if used intermittently. Instead, single use disposable gloves of greater than 15 min breakthrough time should be used for single tasks and discarded. Nitrile gloves of 0.1mm thickness have not been found to be suitable. A 0.2mm nitrile glove was identified as suitable.

• Continue to develop HSL’s permeation testing rig and test further glove/chemical combinations. In particular to investigate discrepancies between test houses, and the influence of chemical concentration on permeation breakthrough time.

• Encourage use of regular biological monitoring to give ownership of exposures to individuals and raise awareness of the importance of reducing personal exposure through behaviour.

• Encourage chemical manufacturers to consider substitution where chemicals are known to give rise to short breakthrough times.

viii

1 INTRODUCTION

1.1 DERMATITIS IN THE PRINTING SECTOR

According to an HSE survey, the printing sector is the 6th largest employer in the UK, employing approximately 170,000 people in 12,000 premises (HSE 2000a), many in small enterprises. Not all of these are “hands-on” printers, as this figure includes back-office staff employed within the sector. About 45,000 are active printers, according to a Sector Information minute.

The chemicals and solvents used in the printing sector are known to cause dermatitis. The HSE research (HSE, 2000a) studied printers in the Nottinghamshire area and showed that:

• 49% of print workers reported they had suffered a skin complaint at some time, although this does not mean that all such complaints were work-related.

• 26% currently had a skin complaint on their hand(s). • 6% had taken time off work because of skin complaints, 39% of these being more than

a week. • People actually involved in the printing process and the subsequent cleaning of the

printing machines showed the greatest tendency towards skin problems, even though over 90% of them wore personal protective equipment such as gloves. The most commonly affected parts were fingers or webs between the fingers, closely followed by the back of the hand, face and forearm. A large proportion of those suffering reported that work-related substances appeared to aggravate a skin condition.

The data was used to estimate a baseline figure of 420 cases per 100,000 workers for the year 2000 for the incidence of dermatitis in the printing industry (HSE, 2005).

1.2 AIMS OF THIS WORK

1.2.1 HSC Strategy The project reported here is part of the campaign to reduce dermatitis in the printing sector under the Disease Reduction Programme, part of The Health and Safety Commission’s strategy to reduce working days lost to occupational ill-health from its baseline 2001 level by 20% by 2010 (HSC, 2004).

This project is closely aligned to the development of a dermal exposure strategy for HSE. It was set up under HSE’s Compliance block of programme work, but is now part of the Disease Reduction Programme within the FIT3 initiative. The interim target for reduction in incidence of ill health due to chemicals, is a reduction of 1,000 by 2007/2008 from the estimated incidence in 2003/2004 of 41,000.. HSE is working with stakeholders to achieve the reduction target through initiatives involving the promotion of new guidance “COSHH Essentials for Printers” (HSE 2006a), which comprises approximately 45 specific, task-related guidance sheets focussed on the different tasks that printers carry out within the different sub-sectors within the printing sector, which are described later.

1.2.2 Guidance for printers currently available

General industry advice for use of chemicals with particular relevance to the skin are given in:

INDG233 Preventing Dermatitis at Work. Advice for employers and employees (HSE, 1996)

1

HSG206 Cost and effectiveness of chemical protective gloves for the workplace: Guidance for employers and health and safety specialists (HSE, 2001a)

INDG330 Selecting Protective Gloves for general work with chemicals (HSE, 2000b), which lists some basic classes of chemicals such as acids/alkalis.

“Rash decisions” (HSE 2001b) is a video in which individuals who have suffered from dermatitis describe the effect that the condition has had on their working and private lives. The cases include a printer.

More specific industry advice is given in:

“COSHH Essentials for printers” (HSE 2006a), a set of guidance leaflets now available from the HSE website containing 45 leaflets and partly developed from this research.

IACL101(rev1) Skin problems in the Printing Industry (HSE 2004), is aimed specifically at dermatitis in the printing industry. It was produced by the Health and Safety Commission’s Printing Industry Advisory Committee (PIAC), which consists of representatives from HSE, the printing industry including the British Printing Industry Federation (BPIF) and printing trade unions. This leaflet shows examples of dermatitis and describes symptoms, and describes actions such as elimination or substitution of chemicals, engineering controls to prevent or avoid dermatitis. It has a table of recommended glove choices for specific organic solvents such as xylene, toluene and methanol.

HSG205 Assessing and managing risks at work from skin exposure to chemical agents: Guidance for employers and health and safety specialists (HSE 2001c)

The printer's guide to health and safety (HSE 2002), a comprehensive book.

1.2.3 Aims

The aims of this project were:

• To obtain quantitative laboratory test data on the permeation of specific chemical mixtures through a range of chemical protective glove materials commercially available for use in the printing industry.

• To form a partnership with stakeholders and carry out field trials using biological monitoring to identify dermal exposures to employees when wearing a range of chemical protective gloves (same materials as in the laboratory study) to protect themselves from dermal exposure to a range of chemical mixtures (same chemicals as in the laboratory study). The stakeholders’ contributions will be ‘in kind’ in providing access to appropriate work activities for the field trials.

• Determine from the recorded data whether there is a relationship between predicted (laboratory measured) glove permeability and actual glove permeability as shown by dermal uptake of the chemicals in mixtures and develop task-based guidance on appropriate chemical protective glove selection for specific work activities.

2

1.3 PRINTING INDUSTRY SUB-SECTORS

The printing sector is divided into several sub-sectors that reflect the different types of printing work. They are:

1. Lithographic 2. Screen Printing 3. Gravure Printing 4. Flexographic Printing 5. Digital Printing

The lithographic printing sub-sector comprises several printing specialisms, and can be divided into three:

1. Non-heatset sheet fed, subdivided into UV and conventional inks 2. Non-heatset web fed 3. Heatset printing

There are three types of inks used: conventional inks, UV cured inks and specific inks for heatset printing.

1.4 OBJECTIVES OF THIS STUDY

This project deals exclusively with the largest sub-sector– the lithographic sub-sector. The field work in this project deals exclusively with the UV lithographic sub-sector.

The objectives were : 1. Identify the chemical mixtures and chemical protective glove materials used by the

stakeholders and observe how the stakeholders normally carries out the specified work activities. To observe how the gloves are used in the workplace and measure their effectiveness through biological monitoring.

2. Develop methodology for biological monitoring if necessary. 3. Purchase samples of the chemical mixtures and chemical protective glove materials to

be tested in the laboratory permeation studies and subsequent field trials. 4. Specify the laboratory permeation test standard. 5. Obtain quantitative laboratory test data on the permeation of specific printing industry

chemical mixtures through a range of chemical protective glove materials commercially available for use in the printing industry.

6. Report on results of laboratory studies setting out proposals for dealing with any problems identified.

7. Specify the range of work activities to be surveyed in the field trials. 8. Plan exposure sampling and monitoring phase with HSE and stakeholders. 9. Carry out field trials using biological monitoring and air sampling to identify dermal

exposures to employees when wearing a range of chemical protective gloves (same materials as in the laboratory study) to protect themselves from dermal exposure to a range of chemical mixtures (same chemicals as in the laboratory study).

10. Analyse the measured exposure data to identify how exposure had occurred. 11. Consider other pertinent factors (degree of touch sensitivity needed to carry out each

activity, glove durability, etc.) to identify the most appropriate chemical protective glove for each work activity and compare findings to the laboratory test data.

12. Review the way each work activity is carried out to determine if it would be reasonably practicable to provide an improved ‘hands on’ approach to reduce exposure risk.

13. Recommend improvements to work practices and glove selection to reduce dermal exposure.

3

14. Revisit the site to put changes into effect and monitor exposure for improvement. 15. Prepare and deliver final study report.

This study has been undertaken in close liaison with CHSD3 (the sponsoring HSE subdivision) and adapted as necessary to keep abreast of developments in the Disease Reduction Programme.

1.5 STAKEHOLDERS IN THIS STUDY

The Health and Safety Commission’s Printing Industry Advisory Committee (PIAC) consists of representatives from HSE, the printing industry including the British Printing Industry Federation (BPIF) and printing trade unions supported this work.

Two UV lithographic printing premises were suggested by BPIF and they were approached. They willingly co-operated and gave us access to their workforce.

1.6 METHOD SUMMARY

The project plan could be condensed into the following steps:

1. Undertake preliminary visits to the participant firms to identify and subsequently analyse the chemicals in use, and identify the gloves used with those chemicals. The opportunity was taken to sample the air and analyse it non-quantitatively for a range of airborne volatile compounds. In parallel with the analyses of liquid solvents, this was to identify possible target chemicals for biological monitoring for dermal uptake, and possible interfering compounds for biological monitoring from inhalation uptake.

2. Identify other common solvents in the lithographic printing sector, and select other gloves made of other materials of equivalent physical robustness, that might be suitable alternatives for the range of chemicals.

3. Construct a laboratory testing specification for the identified chemicals and gloves and tender it to sub-contract to a testing laboratory. At the time that the study was set up, HSL had no test methods for measuring glove permeation or physical properties. A permeation facility has now been set up at HSL as a spin-off project from this one, but it was not available at the time.

4. Undertake first sampling visits to the participant firms to monitor quantitatively the identified volatile compounds in the air, obtain urine samples and check them for the presence of likely chemicals in use.

5. The urine samples from step 4 identified a possible problem area with one chemical during an ink mixing task, but it was unclear whether the dermal had caused the exposure. It was impossible to eliminate the inhalation route in the workplace, so a volunteer study was set up as a separate project at HSL (Cocker et al, 2005) to see if the gloves, properly used, were suitable for the ink mixing task. The laboratory tests were extended to include that chemical.

6. Subcontractor report on glove/chemical laboratory performance.

7. Volunteer study report on problem area glove/chemical performance.

4

8. Following the results of steps 6 and 7, undertake further site visits to implement new recommended glove regimes and experimentally extend some glove use to the second day.

9. Final report.

The rest of the report is set out in the above order to present a logical thread to the narrative. The exception is the laboratory testing contract where the specification (step 3) and the results (step 6) are placed together in Section 4 to give thematic continuity.

5

2 INITIAL SITE VISITS

Initial visits to both sites were carried out under an HSL support project JS20.03606 prior to the main project. The initial site visits were intended to:

• introduce ourselves to the staff and management, • explain the nature and aims of the research, • familiarise ourselves with the tasks that were performed, the chemicals that were in use

for those tasks and the gloves that they were used with, • obtain consent in principle for biological monitoring.

As dermal exposure is often found in parallel with inhalation exposure, static air samples were taken around the sites. These were analysed non-quantitatively at HSL by scanning for a range of airborne inhalable solvent components. This was also used to search for components that could give rise to biomarkers in urine. The consent form for biological monitoring is shown at Appendix 1. This was workplace sampling, and subjects would not be exposed to any substances that they would not be exposed to normally at work. Therefore this type of personal sampling did not require ethical approval.

2.1.1 Sampling and analytical methods Personal and static pumped Tenax samplers were used to sample the air onto Chromosorb 106 sorbent tubes, which were sealed on-site. Initial air samples were subjected to a sweep for organic chemicals using Gas Chromatography with Mass Spectroscopy (GC-MS-MS) and library spectra were used to identify them. Air samples from subsequent visits were analysed for specific chemicals by thermal desorption according to UKAS-accredited method OMS-001 (HSL 2006), using known retention data and a single reference standard of toluene loaded onto Tenax at approximately 30 µg. However, the sampling times were often short, and are not covered by the UKAS schedule. Results are expressed as ppm volume concentration. For diffusive samples, the concentration was determined from the effective uptake rates Ueff (ng/ppm/min) for each analyte onto Chromosorb 106.

Urine samples were frozen on receipt and analysed by GCMS for specific chemicals.

2.1.2 Company A (initial site visits of 22/10/03 and 19/11/03) This is a medium-sized company in the Midlands, but with 12 printers actively engaged in printing at any one time per shift, working in pairs. On the days of the visits, printing was underway of box packaging for pharmaceutical products in sheet form using up to six roller printing presses in a line. The activities that we observed could be divided into three basic tasks: roller cleaning and plate cleaning, both in the main floorspace, and ink-mixing in a separately ventilated room. The ventilation in the main floorspace was reported as 14 air changes per hour.

“Deb Protect” pre-work cream was available in the staff toilets, and actively used; one worker was seen to exit the facility with arms covered to the elbows. According to the safety manager, staff performed regular visual hand-checks to look for onset of skin problems and there were no current cases of work-related dermatitis. The workers themselves chose from the selection available to them, the gloves that they preferred for a particular task, and replaced them whenever they felt the need, generally once per week.

Three activities were identified (Figure 1) that are described in turn below.

6

Figure 1. Roller Cleaning, Plate Cleaning and Ink Mixing.

2.1.2.1 Roller cleaning: This task was to manually clean the machines whenever a job ended or a colour change was required, to recover the unused ink from the top roller with a spatula and to clean all traces from the rollers, impression cylinders, rubber blankets, ink ducts and drip trays using (gloved) handheld cloths. This took approximately 10-15 minutes per roller. They mainly used “Blanco 1” as a roller cleaning solvent. Sometimes a paintbrush was used to apply solvent to the roller from a lidded bucket, sometimes the solvent was squirted from a bottle. Cleaning the bottom roller involved lying on the walkway and reaching up to the roller, and removing the ink drip tray and tipping it to waste. The operators often used just one glove on the left hand to operate the controls to move the rollers round, with the right hand bare to use a tool to recover ink from the top. The right glove was put on to wipe the rollers clean, and to remove and clean the drip tray.

2.1.2.2 Plate cleaning: Thin 1m2 aluminium print plates (plates) were often saved up for batch cleaning by hand wiping. Approximately 2ml of Heavy Duty Plate Cleaner was applied by squirting from a bottle, spread with a sponge in the gloved hand to loosen the ink, then wiped off and rinsed by squeezing the sponge out in a bucket of water. This was sometimes followed by a final wipe with Blanco 1 afterwards. A worker was seen to use only one glove to clean the plate, manipulating the plate carefully by the edges with his bare hand. Another used two gloves but was seen to touch the freshly wiped table surface just after removing them and before it was dry.

2.1.2.3 Ink mixing: Ink was mixed mechanically in a bowl, and scraped out into pots using a spatula in ungloved hands, before donning gloves to wipe out the bowl with rags, using “Ultraking washup” squirted from a plastic bottle. The worker was extremely careful not to touch the ink with bare hands, but did touch it with a fingertip on one occasion, carefully wiping it on a dry cloth immediately afterwards. The mixer blade was wiped with a solvent-wetted cloth, usually in a gloved hand, but on one occasion with a bare hand, avoiding the ink but not the solvent. Tools and work surfaces were cleaned thoroughly afterwards with Ultraking solvent and cloths in gloved hands.

2.1.2.4 Solvent chemicals and gloves The main-use cleaning chemicals and several lesser-used chemicals, all for UV inks, were included as challenge chemicals for the glove permeation tests (Table 1). Other solvent chemicals were used on-site as in Appendix 2. On a later site visit, two more chemicals, Spectrum 5030 and iso-propyl alcohol (IPA), were found in use.

The gloves in use were Ansell-Edmont 37-675 flock-lined 0.4mm nitrile, described by the safety manager as “for heavier work”, and Poly-co 927 Superglove Nitritech II, another 0.4mm

7

flock-lined nitrile glove, described as for “light work”, but they were seen in all parts of the workplace and apparently used interchangeably. A Marigold G25B 0.84mm flock-lined nitrile glove was used for plate cleaning, and a pair was also seen in the ink-mixing room although they were not used during our visit. These three glove types were all included in the permeation tests. An unknown brand of single-use, disposable, 0.1mm, nitrile gloves was reported as occasionally used for the ink mixing task, for plate cleaning and for roller cleaning in hard-to-reach corners such as microswitches, but these were not seen on the visit. They were not included in the permeation tests. Unpowdered natural rubber latex gloves were also reported as used when removing dry rollers, but were not seen on the visit.

2.1.2.5 Results from Company A initial visits 19/11/03 Results for air sampling are at Appendix 4.

All air samples showed the presence of propan-2-ol, which was a constituent of Blanco 1.

One roller cleaner’s air sample (A5) showed that benzoic acid was present and a range of other organics, but this could not be associated with use of any particular different compound. One static sample in a different room (Room 2) also showed these chemicals. Although the results would make more sense if that personal sample (A5) had also come from Room 2, our records identified A2 as the individual working there, whose personal sample did not show the same chemicals as the nearby static sampler. These records were checked for discrepancies but none were found.

1-methoxy-2-propanol, otherwise known as propylene glycol methyl ether (PGME), was present in the ink mixing room air at low levels (10 ppm) but not elsewhere (subject A3). PGME has been subject to a volunteer exposure study in the past (Jones 1997) and urine samples could be related to an equivalent inhalation exposure, and thus to the OEL.

Six spot urine samples were returned by post. They were analysed for the presence of PGME, which we knew was present in high concentration in one of the solvents. One sample was markedly higher than the others, although still at a low level. However, the returned samples were not labelled so could not be linked to an individual. We cannot identify the ink mixer (A3), who used the PGME solvent, from the others, who did not.

2.1.3 Company B (initial site visit of 06/11/03)

This was a small printing works in Northern England. The same roller cleaning and plate cleaning tasks were observed as before, using similar machines. They mainly used “Truwash 4” as a machinery and roller cleaner and “Ultrachem” degreaser. “Nitromors” paint stripper was reported to be used weekly, but not observed on the day. This contains >60% dichloromethane according to its MSDS, but there is a highly specific glove recommendation in the MSDS. For plate cleaning before and after use, they used relatively smaller amounts of “Vulcan Plate Cleaner” (a plate preservative coating), “Spectrum Plate Saver 6045”, gum arabic and isopropyl alcohol (IPA). Ink mixing was not done on this site as they used pre-mixed inks. These were sampled on the initial visit, but were not analysed. The gloves used were 927 Superglove Nitritech II 0.4mm flock-lined nitrile and Ansell-Edmont 37-675 (both seen at the other site). There were no current cases of dermatitis, but one worker had had a recurring problem on one hand.

2.1.3.1 Results from Company B (initial site visit of 06/11/03) Five personal air samples were taken using pumped Tenax tubes. They were analysed for Volatile Organic Compounds using GC-MS and a library to identify. Results are in Appendix

8

5. Quantification values are approximate. Most of the Company B air samples had similar constituents because it was a small works and they all breathed similar ambient air. IPA, C7 hydrocarbons, a few aromatics and limonene (a skin sensitising terpene) were found at concentrations

3 CHEMICAL SOLVENTS USED IN THE LITHOGRAPHIC PRINTING SECTOR

The UV sheet printing industry is a specialist part of the lithographic printing sub-sector. The chemical solvents found in use during the two initial site visits were sampled and analysed to identify organic chemicals, by HSL’s Organic Measurement Section using GC-MS-MS with a spectrum library to identify the constituents. This did not give a fully quantitative analysis but identified major and minor components, which are not reported here but were used to identify those tha t might be suitable for biological monitoring. In addition to the chemicals found in use on-site, an inventory of the complete stock was supplied by one of the firms.

Some of the chemical solvents found on the site visits were not used very often, and some were specific to the UV lithographic sub-sector. There was a danger that, by concentrating only on the chemicals used at the two sites, we might miss families of solvents widely used in the non-UV lithographic sub-sector (Section 1.3). To ensure wider coverage for the project, we contacted two UK chemical suppliers by telephone, and they described their market leaders for the UK lithographic sector:

3.1 ABC CHEMICALS ABC Chemicals biggest selling standard ink lithographic blanket wash is ABC111 (pers. comm.). The chemicals noted in its Material Safety Data Sheet (MSDS) are listed in Table 1. The exact formulation varies a little from batch to batch.

3.2 VARN PRODUCTS The operations manager at Varn Products usefully summarised the lithographic sub-sector in three parts as follows (pers. comm.):

1. Sheet fed printing, subdivided into UV and standard inks. The standard ink washes can be subdivided into two types:

a) manual washes white spirit with aromatics added at anything between 0 and 75%, and a 42ºC flashpoint. These are more aggressive solvents than b) automatic washes containing 61ºC flashpoint conforming to the German "AIII standard".

2. Heat set printing with automatic wash.

These are vegetable oil based with high flashpoint. Rape seed oils are more aggressive

to the skin and can cause sensitisation. Their market leader is Natural Wash (Table 1),

which can be diluted 50-50 with water for manual cleaning during servicing work.

3. Cold set printing (newsprint)

Their market leader is NEWS100 for 100ºC flashpoint (Table 1). An alternative is

NEWS60 for 60ºC flashpoint.

Some of these solvents contain rejuvenators when they are recycled by simple filtration. The rejuvenators contain extra solvents such as glycol ethers.

3.3 CHEMICALS SELECTED FOR LABORATORY TESTS

The set of chemicals selected for glove testing are shown in Table 1. Some of the UV lithographic chemicals were found on-site and the constituents identified by analysis at HSL,

10

and some were market leaders for the rest of the lithographic market. These were sent directly to a glove test house, and were not analysed by HSL.

TABLE 1. Chemicals selected for laboratory tests

Chemical Manufacturer Main Risk phrases Use on-name constituent(s) according to site

according to MSDS visits? MSDS

Heavy Duty Varn Products Solvent naptha Xn, C, Yes. Plate Plate 30-35% R51/53, R65, cleaning Cleaner Phosphoric acid 66, 67, R34

1-2% News 100 Varn Products Light petroleum Xn: R65,66 No. Wash distillates 60 Newsprint

100% Market leader

Natural Varn Products Light petroleum Xn: R65,66 No. Wash distillates 40

90% N: R10,22,38, 41, R51/53

Newsprint market leader

Blanco 1 Varn Products Napthas Xn: R65, Yes.

Mesitylene 1-5% Cumene

product found on-site but not included in Table 1 for glove tests also contained 10-30% terpenes (Appendix 2). The products are for dilution with water before use.

Several of the MSDSs of the compounds used the risk phrase R66 “Repeated exposure may cause skin dryness or cracking”. The MSDS for the plate cleaning compound carried the risk phrase R34 – “Causes burns”.

The products in the two last rows of Table 1 are compounds that were submitted at a later time to the glove test house as an extension of the original contract.

A linked HSL study (Simpson and Unwin, 2006) was set up to identify further chemical solvents in use in the printing industry for all sub-sectors, i.e. not just the lithographic sub-sector, and to develop a permeation testing facility to test a selection of solvent products against a selection of gloves. The set of chemicals in Table 1 was sent to the external glove test house for performance testing while the facility was developed at HSL.

12

4 LABORATORY GLOVE TESTING SUBCONTRACT SPECIFICATION AND RESULTS

4.1 TENDER SPECIFICATION

The specification for the tender for a glove-testing subcontract was developed by the HSL Organic Measurement Section and the HSE technical customers CHSD3 as part of the initial support work (job no. JS20.03606). The specification was a combination of physical and chemical challenge tests and is given below. The winning bidder, Kächele-Cama Latex GmbH (KCL) received the invitation to tender (Tender Ref T16/034) on 12th of September 2003 and quoted to it on 17th of September 2003. The contract for the Protective Glove Test (HSL Ref HSLSC403 (JR51.253) was signed on 6th of February 2004.

KCL also volunteered additional tests at no extra charge to HSE. These are shown in italics below.

4.2 TENDER

For each combination of seven glove types and seven chemicals to be specified and supplied by HSL – a total of 49 combinations:

Chemical exposure prior to physical testing will be carried out at 23 ± 1°C (as per BSEN 374-3 permeation tests). There is no requirement for ageing or toxicological studies. At least three valid results are required for each exposure condition, test, glove material and chemical.

KCL volunteered to compare their own equivalent gloves at no extra charge to HSE.

4.2.1 Breakthrough (Permeation) Chemical Tests

The subcontractor will carry out the laboratory permeation tests to the requirements of BSEN 374-3 on all combinations of the glove materials and chemical mixtures (supplied by HSL), although it is realised that some modification to the methodology given in the standard may be required for the mixtures. Breakthrough times are required, with a minimum number of three valid test results per combination of chemical and material. For the purposes of this study, the identification of the chemical making primary breakthrough is not required, although if this can be done, the subcontractor should provide additional details.

4.2.2 Physical Tests

4.2.2.1 Puncture, as received condition: Each glove material will be tested according to the principles of EN 388:1994 for resistance to puncture, both with and without exposure to each of the chemicals listed below, at 23 ± 1°C only. Materials are to be tested as received without any conditioning or pre-treatment (except chemical exposure where relevant).

13

4.2.2.2 Puncture, following permeation testing:

One glove of each pair will be externally exposed to the chosen chemical for a period equivalent

to the measured minimum breakthrough (or a maximum of 480 minutes if no breakthrough is

detected) as determined above. Samples for the different tests will be cut from equivalent areas

of the left and right glove. Testing of exposed samples must be commenced within 10 minutes

of removal from the chemical. Results for each sample will be reported for measured puncture

resistance in Newtons. Observations of any difference in mode of failure between non-exposed

and exposed samples are required.

4.2.2.3 Puncture, if a difference is found above:

For each glove/chemical combination showing a change in resistance to puncture of >10%

following exposure (compared to the unexposed glove) for the minimum breakthrough time (or

a maximum of 480 minutes if no breakthrough is detected), a further set of puncture tests will

be carried out on samples exposed for half the minimum breakthrough time.

4.2.2.4 Swelling, (degradation): Chemical exposure prior to physical testing will be carried out at 23 ± 1°C. NB This was not specified in the tender but volunteered at no extra charge.

4.2.2.5 Penetration: A penetration test according to BSEN374-2 will be carried out to test unused gloves for leak tightness. NB This was not specified in the tender but volunteered at no extra charge.

4.3 EXTENSION TO THE CONTRACT

The initial contract was for seven glove types and seven chemicals (49 combinations), however in the event, eight glove types and six chemicals (48 combinations) were submitted. A further two chemicals were submitted at a later stage (Care Gel and Ultraking washup) as an extension to the contract after it became apparent that these two chemicals were used at the sites visited, but had not been included in the permeation tests, and that at least one of them could be a problem. The contract was extended and the final report covering the original and extended chemicals, was delivered in March 2005.

4.4 GLOVE PERFORMANCE – SELECTION CRITERIA

The following glove types were tested (Table 2). Details of the levels of chemical and physical categories are given in Table 3. Figures for abrasion resistance, cut resistance, tear resistance and puncture resistance are quoted from manufacturers’ literature, as obtained in accordance with the test methods in the sections 6.1, 6.2, 6.3 and 6.4 of EN 388 : 1994

The set of gloves included those that were found on the premises during the initial field visits (Section 4), which had been selected primarily for abrasion resistance according to the safety manager. Further gloves were selected by HSL as possible practical alternatives. They were selected to cover different materials, but to have similar durabilities according to the physical data. However, some durability was sacrificed to retain flexibility and dexterity where this would otherwise have overly increased the thickness of some of the materials. Cost was also an issue, and the gloves were selected to be in a similar price range to offer a practical and affordable alternative, should one be found.

A group of nitrile 0.4mm gloves were chosen to compare differences in performance between brands, which may be caused by different manufacturing methods. Nitrile rubber contains two copolymers, the proportions of which affect the degree of chemical or physical protection,

14

although investigating this particular aspect was not part of this project. Two similar types of Ansell-Edmont gloves were selected, one with a flock lining and one without. KCL added their own brand of gloves to the tests over and above the subcontract, although their durability was different to the HSL selection criteria. KCL also added some thinner gloves as an extra option.

Table 2. Glove details according to manufacturers’ information taken from data sheets, packaging of testing gloves, or other sources of the individual

manufacturers (from KCL report)

Manu- Glove Material AQLa Thick- EN 388 Length Design facturer Level ness Physical

data b

Marigold G25B Blue Nitrile

Nitrile 1.5 %

Level 2

0.84 mm 4 1 0 1 33 cm Flock lined nitrile

Ansell 37-655 Solvex Nitrile 1.5 %

Level 2 0.38 mm

3 1 0 1 (4102)c

33 cm Unlined nitrile

Ansell 37-675 Solvex Nitrile 1.5 %

Level 2 0.38 mm

3 1 0 1 (4102)c

33 cm Flock lined Nitrile

Poly-co 927 Superglove Nitri-Tech II

Nitrile 1.5 %

Level 2 0.38 mm 4 1 0 1 31 cm Flock lined nitrile

KCL 730 Camatril

Nitrile 0.65 % Level 3 0.4 mm 2 1 0 1 31 cm Flock lined nitrile

KCL 743 Dermatril P

Nitrile 0.65 % Level 3 0.2 mm 0 0 0 X Thicker disposable nitrile

KCL 740 Dermatril

Nitrile 0.65 % Level 3 0.11 mm 0 0 0 X

Thin gauge disposable nitrile

Marigold G44R Tripletec

Nitrile / Natural Latex

1.5 % Level 2

0.98 mm 4 0 2 1 32 cm Flock lined material mix

Marigold 1651ME101 Emperor

Natural Latex

1.5 % Level 2

2.2 mm 4 1 2 1 26.7 cm

Unpowdered unlined natural latex

North 604 Strongoflex PVC 1.5 %

Level 2 1.3 mm 4 1 2 1 40 cm PVC with cotton jersey

Showa 660-11 Showa

PVC 1.5 %

Level 2 1.5 mm 4 1 2 1 30 cm PVC with cotton jersey

KCL 720 Camapren

Chloroprene

0.65 % Level 3

0.65 mm 1 1 1 1 30 cm

Flock lined chloroprene

a Definition of AQL: Share of faulty units in %. AQL of 0.65% = 0.65 faults per unit of 100 (Table 3)

b Key to physical data: numbers represent abrasion, cut, tear, puncture, in that order.

c The outer packaging of the Ansell–Edmont Sol-vex 37-675 gloves indicated that the mechanical performance was 4102, rather than the 3101 quoted in the KCL report. Ansell-Edmont marketing literature also quotes 4102.

15

Table 3. Chemical and Physical data codes used in Table 2

Test Level 1 2 3 4 5 6

EN 388

EN 388

EN 388 10 25 50 75

EN 388 20 60

EN374-2 Level AQL (%)

EN 374-3 10 30 60

Test standard Level Level Level Level Level

Abrasion resistance (cycles) 100 500 2000 8000

Cut resistance (factor) 1.2 2.5 5.0 10.0 20.0

Tear resistance (Newton)

Puncture resistance (Newton) 100 150

Acceptable Quality 4.0 1.5 0.65

Permeation BTT (mins)

120 240 480

Results >480 minutes are similarly marked in tables later in this report. This is to highlight the “best-performing” gloves.

. Authors note: A BTT Level 6 glove that lasts for a full 8 hour shift (>480 minutes) is marked here in white on grey

4.5 BRIEF DESCRIPTIONS OF THE GLOVE TESTS

This section is intended as background information for those unfamiliar with methods used in glove standards tests. It is not definitive, and readers are referred to the standards themselves for more detailed information.

4.5.1 Breakthrough (Permeation) Chemical Tests

Laboratory permeation tests to the requirements of BS EN 374-3. A piece of intact glove material is clamped between two plates in a test cell (Figure 2). The test liquid is poured via the upright tube into one side of the cell. Clean air flows continuously through the other side of the cell, exiting to a vapour detector. The test is deemed to have finished when vapour is detected at a rate equivalent to permeation through the glove material of 1.0 µg.cm-2.min-1.

Figure 2 Permeation cell

16


Puncture, as received condition:

The test was carried out according to EN 388, as follows: A piece of glove is clamped to a ring. A specific shape and sharpness of needle is pushed up from below the sample glove with a velocity of 100 mm.min-1, and stopped either at a maximum of 50 mm travel or at breakage (Figure 3). The force of the needle is recorded at breakage or at 50 mm travel. The test was carried out with 4 different samples cut from the palm or back (a flat area) of the same glove type, and the lowest value of 4 test results is reported.

Figure 3. Puncture test rig (from KCL report p28)

photo reproduced by permission of KCL GmbH

Swelling (degradation): Chemical exposure prior to physical testing will be carried out at 23 ± 1°C (the same temperature as the BS EN 374-3 permeation tests). Two 30 mm discs cut from the palms of two gloves are immersed in the test chemical, and the relative (percentage) change in linear diameter is measured at intervals up to 22 hours (Figure 4). NB This test was not specified in the tender but volunteered at no extra charge. KCL performed their own normative test (ref QU). Both the inside and outside of the glove are exposed to the chemical at once, whereas in the permeation test, only the outside is exposed.

17

Figure 4. Swelling test (from KCL report p27)


As it is their own test, KCL have their own recommendations. The interpretation of the swelling characteristics are reported in accordance with KCL internal policy and does not relate to recommendations in normative standards. KCL provided the following explanation and interpretation: (quoted from KCL report) “As a policy, KCL also tests the degradation of the material with every permeation test. KCL recommend that only protective gloves that show a lower degradation than 6.8% after 8 hours, should be used. However, this is not a requirement of EN374.

Degradation Assessment within 8 hours by KCL

< 6.8% + (resistant) < 15.0% o (partially resistant) > 15.0% - (non resistant)

Even if a glove is not broken through, the mechanical and therefore protective properties of the glove can be changed under the influence of a chemical by degradation (damage). Generally, a degradation is immediately visible – for example, the glove swells, shows leaks, gets out of shape or becomes stiff. Degradation often causes permeability of the chemical that caused it, so that the degradation is already noticed during the permeation test. In some cases, degradation causes a compression of the material, which has the effect that chemical resistance is improved, the mechanical properties (grip, dexterity), however, are impaired.”

Penetration: a penetration test for leak tightness according to BS EN 374-2 was carried out prior to each test on an unused glove. The leak test was by inflating the glove and checking for pinholes and splits. NB This was not specified in the tender but volunteered at no extra charge.

4.6 GLOVE TEST RESULTS

4.6.1 Breakthrough (Permeation) Chemical Tests Laboratory permeation test results to the requirements of BSEN374-3 are given in the KCL report by chemical (8 tables). They are re-tabulated here in condensed form by chemical and glove (Table 4).

18

Table 4. Results of permeation studies (data from KCL report)

erial Thick-ness in

mm Plate Cleaner

1 ABC Meter

X king

Nitrile >480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

Nitrile >480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

Nitrile >480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480 >480

91 95 89

co Nitrile >480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

>480 >480 >480

27 31 35

20 22 28

17 15 14

>480 >480 >480

41 43 45

>480 >480 >480

>480 >480 >480

73 75 78

24 25 29

16 17 19

5 7 6

Nitrile / Natural Latex

>480 >480 >480

70 81 75

45 47 50

93 95 99

18 25 22

12 15 12

30 32 35

71 62 63

Natural Latex

>480 >480 >480

96

98

36 37 41

26 27 35

59 65 62

Showa PVC>480 >480 >480

>480 >480 >480

>480 >480 >480

84

92

PVC>480 >480 >480

>480 >480 >480

>480 >480 >480

47 47 65

>480 >480 >480

19 22 21

13 15 17

29 32 35

39 47 42

.

Glove Mat- Care Gel Heavy Duty

News100 Natural wash

Blanco 111

Ultra-

G25B Marigold 0.84

220 215 232

169 156 151

37-655 Ansell 0.38

200 205 195

129 135 132

37-675 Ansell 0.38

465 450

280 220 268

927 Poly- 0.38 180 192 177

164 179 161

730 KCL Nitrile 0.4 337 340 333

121 135 137

743 KCL Nitrile 0.2 229 240 237

196 198 207

740 KCL Nitrile 0.11

G44R Marigold 0.98

1651 Marigold 2.2

205 210 207

100 155 158 168

187 110 124

660-11 1.5 461 475 468

373 380 382

156 157 165

134 138 135

118

604 North 1.3

342 350 348

142 145 154

113 117 121

123 123 128

720 KCL Chloroprene 0.65 168 172 170

162 165 167

222 225 227

Authors note: a Level 6 glove that lasts >480 minutes is marked here in white on grey

19

It is apparent that the top 5 gloves in Table 4, nitrile gloves of at least 0.38 mm thickness, performed best for the greatest number of the chemicals for up to 8 hours. Latex, chloroprene (neoprene) and PVC gloves did not perform as well for the full range of chemicals.

An information leaflet issued by Marigold gloves quoted longer breakthrough times for G25B gloves to 1-methoxy-2-propanol than were found by KCL (see Discussion section).

Two of the chemicals presented a particular permeation problem to all gloves tested. Ultraking washup contains >99% 1-methoxy-2-propanol, which is known to penetrate the skin readily, and has a detectable biomarker in the urine. Meter X contains aromatic napthas (petroleum distillates) that are also found in several of the other chemicals tested, but also contains butoxyethoxyethanol, also a known skin penetrant. Although no urinary marker was available for butoxyethoxyethanol, it was thought that a method to detect one could probably be developed. Meter-X also contains terpenes, which are well known skin sensitisers. These are common additives as fragrances, in particular in the form of limonene.

Meter-X is used in dilution rather than as concentrate, so the glove recommendation should reflect the dilution. The top five gloves from Table 4 are significantly better than the rest, and would probably also be suitable for use for up to 8 hours with diluted Meter-X. The possibility that the diluted product could dry out on the glove between spells of use, increasing the strength again, should also be taken into account.


4.6.2.1 Puncture: as received condition:

The results are given in Newtons in the KCL report and included here in Newtons in Table 5.

4.6.2.2 Puncture: following permeation testing at BTT:

The results are given in Newtons in the KCL report and in Appendix 3. They are summarised in

Table 5 as percentage change from the original condition.

20

Table 5. Percentage difference in Puncture Resistance before and after break-through time or 480 mins (data from KCL report)

Before % difference from “Before” result (Newton) after 100% break-through time (or 480 mins)

Glove Material Thickness in

mm

Original puncture resistance

Care Gel

Heavy Duty Plate

Cleaner

News100 Natural wash

Blanco 1 ABC 111

Meter X

Ultra-king

G25B Marigold Nitrile 0.84 68 -11 -66 -24 -24 +16 -50 -67 -66 37-655 Ansell Nitrile 0.38 60 -11 -60 +11 +10 +24 -50 -75 -59 37-675 Ansell Nitrile 0.38 59 -15 -59 +11 +11 +38 -37 -69 -71 927 Poly-co Nitrile 0.38 46 +2 +2 +6 +6 +17 -2 -16 -24

730 KCL Nitrile 0.4 71 -45 -71 +3 -13 +11 +7 -81 -81 743 KCL Nitrile 0.2 18 -11 -37 +12 +12 +86 +44 +11 -35 740 KCL Nitrile 0.11 15 -34 -74 -31 -38 -61 -53 -73 -66

G44R Marigold Nitrile/Latex 0.98 26 -15 -51 -62 -62 -25 -63 -32 -21 1651 Marigold Nat. Latex 2.2 42 -35 +9 -10 -10 -46 -38 -18 -12 660-11 Showa PVC 1.5 46 -20 -25 -10 -12 -26 -42 -37 -45

604 North PVC 1.3 41 -17 -11 +4 -10 +20 +16 -6 -11 720 KCL Chloroprene 0.65 33 -49 -48 -56 -43 -12 -23 -62 -47

Key: bold = no breakage White on grey = Difference

4.6.2.3 Puncture: at 50% BTT if a >10% difference is found between tests as received and at BTT:

The results are given in Newtons in the KCL report and also as percentage changes from the original condition. Only the percentage changes are included here, in Appendix 3. Only the gloves not marked in white on grey above were required to be re-tested under the contract, as those gloves with least change in puncture after BTT would have a similar change at 50% BTT.

4.6.2.4 Swelling (degradation):

Full results are given in the KCL report by chemical (8 tables). They are re-tabulated here in

The areas in in the table showed that, once condensed form by chemical and glove (Table 6). As it is their own test, KCL have their own recommendations (see Section 4.5.2). white on greyagain, 0.4 mm nitrile gloves were the most suitable across the broad range of chemicals (swelling

Table 6 Degradation (swelling) test by immersion for 8 hours (data from KCL report)

% swelling after 8 hours contact

Glove Material Thick

mm

Care Gel

Heavy Duty Plate

Cleaner

News Natural wash

Blanco 1

ABC Ultra-

Nitrile 0

3.3 3.3

6.6 6.6 10

0 0 0

0 0 0

0 0 0

10 10

13.3

33.3 33.3 33.3

20 23.3 20

Nitrile 0 0 0

3.3 6.6 6.6

3.3 3.3 0

3.3 0 0

3.3 3.3 3.3

13.3 13.3 16.6

33.3 33.3 33.3

20 20

23.3

Nitrile 3.3 0

3.3

3.3 6.6 6.6

0 0 0

0 0 0

3.3 3.3 3.3

10 10

13.3

26.6 26.6 26.6

20 20 20

3.3 3.3 0

3.3 6.6 3.3

0 0 0

0 0 0

0 0 0

10 10

13.3

30 26.6 30

23.3 20 20

6.6 6.6 6.6

10 10 10

3.3 0 0

3.3 0 0

3.3 0 0

16.6 16.6 16.6

36.6 36.6 36.6

26.6 26.6 26.6

6.6 6.6 6.6

20 20 20

3.3 0 0

6.6 6.6 6.6

13.3 10

13.3

23.3 23.3 23.3

46.6 46.6 46.6

30 26.6 26.6

3.3 3.3 3.3

20 20 20

3.3 0 0

10 6.6 6.6

13.3 10 10

23.3 23.3 23.3

36.6 36.6 36.6

26.6 30

26.6

Nitrile/Latex 3.3

0 3.3

13.3 20 20

46.6 46.6 46.6

46.6 46.6 46.6

56.6 56.6 56.6

56.6 56.6 56.6

23.3 23.3 23.3

10 10

13.3

0 0

3.3

3.3 6.6 6.6

53.3 53.3 53.3

46.6 46.6 46.6

63.3 63.3 63.3

63.3 63.3 63.3

13.3 13.3 16.6

3.3 3.3 3.3

PVC 3.3 3.3 3.3

13.3 13.3 16.6

13.3 16.6 13.3

13.3 13.3 13.3

16.6 13.3 16.6

16.6 16.6 23.3

46.6 46.6 46.6

3.3 3.3 0

PVC 0 0

3.3

13.3 13.3 13.3

13.3 13.3 13.3

13.3 13.3 13.3

16.6 16.6 13.3

23.3 16.6 23.3

33.3 33.3 33.3

0 0

3.3

3.3 3.3 3.3

10 10 10

40 46.6 40

43.3 43.3 43.3

50 50 50

53.3 53.3 53.3

33.3 33.3 33.3

13.3 10 10

Key:

ness in 100 111 Meter X

king

G25B Marigold 0.84

37-655 Ansell 0.38

37-675 Ansell 0.38

927 Poly-co Nitrile 0.38

730 KCL Nitrile 0.4

743 KCL Nitrile 0.2

740 KCL Nitrile 0.11

G44R Marigold 0.98

1651 Marigold Nat. Latex 2.2

660-11 Showa 1.5

604 North 1.3

720 KCL Chloroprene 0.65

white on grey = swelling

4.6.2.5 Penetration: Approximately 40 gloves were used of each type in these tests. There were 12 types. All samples passed this test, apart from two 604 Strongoflex gloves which had leaks (Figure 5). Although leaks were detected, the gloves were still used in permeation tests as the affected areas were avoided. Both individual gloves lasted >480 mins in their permeation tests, the same value as their more perfect replicates. Considering that the AQL’s were either 0.65% or 1.5%, between three and seven faulty gloves, i.e. more than just two faulty gloves, would be expected out of the entire 480 tested. However, the two leaking gloves were from the same batch with AQL of 1.5%. Two gloves (Y) out of n=40 is 5% (p=0.05). Using the observed probability, and a normal distribution as an approximation of a binomial distribution, the lower confidence limit L for p is given by

__________ L = Y - Z1-α/2 √(Y(n-Y)/n3) (two-sided) (Conover p 130)

n

For 95% confidence α =0.05, L is negative and therefore less than 1.5%. We conclude that two failures in 40 does not exclude the possibility that the gloves still meet the AQL of 1.5%

Figure 5. Two gloves that failed the leak test. (from KCL report, p30)


24

5.1

5 MAIN SITE VISITS

MAIN SAMPLING VISIT TO COMPANY B (21/9/04)

Two subjects were monitored during the day of the visit, one who carried out roller cleaning and plate cleaning, and one subject who only carried out roller cleaning. No ink mixing was done. Tenax personal pumped or passive air samplers were used, and Permeatec® pads beneath the gloves. Results are in Appendix 5. Subjects used the same types of gloves and used the same chemicals as were found in the initial visits.

Concentrations of trimethyl-benzene (TMB) were found in the air during both plate and roller cleaning of approximately 10ppm, except for one 30 minute sample of 27ppm. The 8-hour WEL for TMB is 25ppm, so the exposure over the day was probably below the WEL. During roller cleaning, there were higher concentrations of up to 140 ppm of aliphatic hydrocarbons from C6 to C11.

One subject (B1) did not use a glove on one hand during a (video-ed) short plate-cleaning task. His Permeatec® pads showed levels of aromatic hydrocarbons and tri-methyl benzene (TMB) ten and twenty times higher respectively, for the ungloved hand than for the gloved hand during both plate and roller cleaning. Heptane (C7 aliphatic) was similar for all hands (

5.2

Company B urine levels DMB

0

10

20

30

40

50

60

70

/

B1 B3 B2 B5

DM

B m

mol

mol

06:00 09:00 12:00 15:00 18:00

Time of sample (open symbol = estimated time)

Figure 6 Urinary dimethyl benzoic acid during main site visit to Company B

FIRST SAMPLING VISIT TO COMPANY A (18/6/04)

Two subjects who carried out roller cleaning, and two subjects who carried out ink mixing, were monitored during the day of the visit. Subjects used the same types of gloves and used the same chemicals as were found in the initial visits. One subject carried out Plate cleaning. Tenax personal pumped air samplers were used, with a static sample in parallel in one instance. Permeatec® pads were used to monitor beneath the gloves. Results are in Appendix 4.

Analysis was confined to PGME, which was used in almost pure form in the ink mixing task but had also been found previously in the urine of non-ink-mixers.

Air concentrations of 50-70 ppm were found for PGME in the short ink-mixing task in the ink-mixing room. This was below the 8-hour WEL for PGME of 100 ppm. The roller cleaners in the main floorspace had PGME levels of less than 0.2 ppm.

PGME was found at low levels (

5.3

It was not certain whether the urinary PGME had been caused by the inhalation of 50-70 ppm or by dermal contact through permeation or other means. The results suggested that the type of gloves in use could leave the skin at risk of contact with PGME. A special return visit to carry out the task again when breathing clean air through a hood or respirator was considered, but rejected as impractical in the workplace. Instead a volunteer study was set up to replicate the task under controlled conditions at HSL (see Section 6).

OCCUPATIONAL HYGIENE EVALUATION DURING FIRST VISITS: GOOD PRACTICE

It was not the purpose of this project to single out either site for specific criticism, so this section refers to observations at both sites. Occupational hygiene observations by an HSE Specialist Inspector at both sites indicated that good practice was the norm, and that lapses were occasional and minor. The benefits of these practices were evident as there were no current cases of dermatitis. General: Clean, tidy ink store. Bright, airy workspace – not cluttered. Roller cleaning: Lack of ink stains around the printing machine. Evidence of good housekeeping.

Wearing both gloves to clean the machine.

Ink-stained tools cleaned immediately.

User’s names marked on cuffs of both gloves to identify the owner.

Cleaning the outsides of the gloves with a cloth, which reduces ink runs down the cuffs.

Using a brush to apply solvent to reduce glove contact with the solvent.

Solvent pot covered with a lid to reduce vapours.

Covered (lidded) bin placed nearby to receive wet cloths and waste liquids.

Prepare a protected area before the task starts with paper or clean cloths, to drop dirty cloths

onto.

Taking care to drop cloths onto prepared area.

Tipping liquids into bins near machine without having to carry them away (risk of spills).

Lying down on a sheet of clean paper to access awkward areas (his white shirt was spotless).

Cuffs turned back to catch ink runs when working overhead.

Good glove removal technique.

Plate-cleaning: Controlled use of cleaning fluid – minimising splashes. Ink-mixing: Good avoidance of ink when using bare hands to handle tools and the mixing bowl, donning

gloves before starting to use the solvent.

Efficient recovery of ink - didn’t spill a drop.

Inadvertent ink stains on hand wiped away immediately with a dry cloth (no solvent).

Application of solvent close to target surface at a controlled rate to reduce splashing.

Good clean up of stray drips.

Thorough clean-up using minimal amounts of solvent.

Good glove removal technique.

It is difficult to describe using rags in gloved hands as “good” practice if better systems of work

can be put in place that reduce, or even eliminate, such close contact with the chemicals. The

principles of “safe working distance” should apply whereby a distance is kept between user and

chemical through the use of tools or containment. The author considers the use of the word

“safe” to be emotive here, and perhaps “safer” should be adopted as a better standard phrase.

27

5.4 OCCUPATIONAL HYGIENE EVALUATION DURING FIRST VISITS: “LESS GOOD” PRACTICE

Although a good standard of hygiene was seen throughout, inevitably there were occasional lapses of concentration that caused ink or solvent to come into contact with the skin. There were also examples of stained worktops that showed the history of use of the workplace, rather than the current practice. Examples of “less good” practice are listed below and shown in Figure 7, but it must be emphasised that these examples are selective and not typical.

Roller cleaning: Working quickly, leading to the odd unnecessary splash.

Use of odd gloves of different sizes and/or brands (Fig 7a).

Handling of ink-stained control panel with bare hands (Fig 7b).

Decanting waste into a bin involving a journey down steps carrying an unstable tray of liquid.

Storing gloves beneath an upturned ink pot lid, transferring ink to cuff area of gloves (Fig 7c).

Untidy stained worktop – shows the history of the workplace (Fig 7d).

Left hand glove on floor inside out showing heavy ink stains on the fingers (Fig 7e). The

turned-up cuff suggests that it has been used inside out as a right hand glove for roller-cleaning.

Plate-cleaning: Perhaps should consider using an apron if leaning over table.

Open containers on worktop, stains on table top.

Chemicals spilt onto bench.

Wiping the plate with one gloved hand but touching the plate with a bare hand (Fig 7f).

Touching the wetted sponge with a bare hand picking up residues of cleaning agent.

Ink mixing: Using a solvent–soaked pad in a bare hand to wipe the paddle – lack of awareness of hazard

from solvent.

Poor glove removal technique.

a) odd gloves (DSCN0703) b) bare hands (DSCN0646) c) glove storage (DSCN0693)

d) stained worktop p(1010057) e) glove used inside out (p1010067) f) one glove (p1010071)

Figure 7. Examples of “less good” practice seen in the workplaces

28

6 LABORATORY VOLUNTEER STUDY

The discovery of low but measurable quantities of PGME in the urine of some of the workers at Company A prompted an investigation as to whether the uptake was via the dermal route or the inhalation route. That investigation is reported in full in an HSL internal report (Cocker et al, 2005). This section summarises that work.

The task that used the most PGME was ink mixing in a separately ventilated room in the workplace. The task only took a few minutes at a time, but might be carried out several times in a day. The same pair of 0.4mm nitrile gloves was used each time during a period of at least a day. It was originally proposed to eliminate the inhalation route through use of a breathing mask supplied with fresh air in the workplace, but this would have placed too great a burden on the workforce. It was considered that a compressed air-line would encumber the subject and affect production. It would be necessary to wear the mask for the entire shift to eliminate the inhalation route even when not carrying out the task itself, and this was unacceptable.

Instead, the laboratory study was set up at HSL in a small chamber. The volunteer subjects undertook successive repeated cleaning tasks using the solvent for half an hour, after watching a video of the technique used in the printing works. They wore an air-fed visor to eliminate the inhalation route completely. Dermal exposure measurements were made using absorbent Permeatec® pads on the fingers underneath new gloves. The volunteers’ complete urine was collected for the 24 hours following the exercise. The study was conducted with ethical approval via the HSE Research Ethics Committee.

Dermal exposure of the hands inside the gloves was limited to the vapour in the air circulating around the subjects and entering the glove via the cuff, which accounted for at least 99% of the PGME absorbed by the under-glove pads when compared to a control test where the gloves were sealed with tape at the wrists (Figure 8).

1

10

GlGlGlPriPri

Means and Standard Deviations of the Permeatec pads

100

1000

10000

Cha

mbe

r

PA

LM

KNU

CKL

E

THU

MB

FOR

EFI

NG

ER

Thum

b

Fore

finge

r

Dominant Hand Lesser Hand

Perm

eate

c (µ

g)

ove 1 ove 2 ove 2 Taped nter 1 nter 2

Figure 8. Arithmetical means and s.d.’s of Permeatec® hand and chamber air measurements in volunteer study (reproduced from Fig 9 of report BM/2005/01)

29

No traces of solvent were found in their urine afterwards. The study concluded that the gloves, properly worn, were suitable for the ink mixing task, even if it was repeated several times in succession, for a period of up to half an hour.

However, it could not answer the question whether the gloves could be used with a different work pattern, i.e. the task repeated intermittently over the entire day or successive days using the same pair of gloves.

This question was subsequently answered by an extension of the laboratory glove permeation study, when 1-methoxy-2-propanol (PGME) was added to the list of test chemicals (Section 4).

This showed that the breakthrough time for the 0.4 mm nitrile Ansell-Edmont 37-675 gloves was 90 minutes (Table 4). Curiously, the unlined version of the same glove lasted longer (130 minutes, Table 4. The thicker Marigold G25B nitrile gloves that were sometimes used lasted slightly longer at 150 - 170 minutes (Table 4)1. The 0.4 mm nitrile SuperGloves lasted longest at 160-180 minutes. An example of a 0.1 mm nitrile single-use disposable glove lasted only 5 minutes, not long enough for one complete ink mixing task after allowing for a reduction due to flexing and temperature. An example of a 0.2 mm nitrile single-use disposable glove lasted 14 minutes. Even allowing for reduction due to flexing, this was considered long enough for a single ink mixing task.

The recommendation from the volunteer study and the permeation testing was that the 0.4mm nitrile gloves were not adequate to use intermittently over the day, and should not be used for several days in succession. A 0.2 mm nitrile single-use disposable glove is recommended, which must be disposed of after each mixing task.

1 An information leaflet issued by Marigold gloves quoted longer breakthrough times for G25B gloves (see Discussion section).

30

7.1

7 FINAL SITE VISITS

RETURN VISIT TO COMPANY A 21/4/05 AND 22/4/05

A two-day visit was made to study the effect of prolonged use of the same pair of gloves. The permeation tests had shown that the nitrile gloves were the best choice for the Roller Cleaning agent, “Blanco 1” wash (Table 4). The occupational hygiene inspector noted immediately that the general tidiness of the workspace had improved since our last visit. The workforce had been concerned that the chemicals they were using could be found in their urine, and were motivated to reduce their own exposures.

Eight subjects were monitored for air, underglove and urine on the first day. The firm saved up a batch of plates for the visit, and one subject was monitored whilst Roller Cleaning in the morning and Plate Cleaning for two hours in the afternoon. Five subjects carried out Roller Cleaning only, using 0.4 mm nitrile Ansell-Edmont 37-675 gloves. Two more subjects were monitored whilst they carried out ink mixing with the new type of gloves, although they would have carried out other tasks as well during the day that were not monitored. They used the 0.2mm nitrile gloves as single-use disposables, rather than the 0.4 mm nitrile for the whole day.

On the second day, three of the five subjects above were monitored carrying out more Roller Cleaning wearing the same pair of gloves as on the first day. One more Roller Cleaning subject was monitored wearing his same pair of gloves as on the first day, but who had not been monitored on the first day. The same two subjects as on the first day carried out further ink mixing with single-use disposable gloves.

Dipropylene glycol methyl ether (DPGME),also known as butoxy-ethoxyethanol, was found in air, under the gloves and in urine . However the substance was not identified as a constituent of the solvents that the printers were using, and it may have arisen from the inks or from unreported solvents. No exposure studies have been found for this substance to compare uptake (urinary monitoring) with an equivalent inhalation exposure OEL. This substance was adopted as a comparative marker in air and urine for Plate Cleaning and Roller Cleaning exposure, but resulting exposures could only be ranked.

It was impractical to seal the cuffs of the gloves onto the five Roller Cleaners’ and the one Plate Cleaner’s hands to eliminate the airborne route, as was done in the volunteer study, because the gloves were constantly being donned and removed. However the cuffs of the ink-mixers gloves were sealed with tape for each job to prevent ingress of vapours in the air.

Results for air, underglove and urine samples are given by subject in Appendix 6.

7.1.1.1 Plate Cleaner

The Plate Cleaner (A14) carried out consecutive plate cleans over 112 minutes starting with new gloves. His pumped Tenax air sample showed low concentration of DPGME of 6 ppm during the task. His underglove measurements were relatively low, ranging from 11 to 29 µg of DPGME (Table 7). His urine showed no detectable DPGME at the start of the shift, but low concentrations of 4 to 6 mmol DPGME per mol of creatinine were found later that day and the next. Other tasks that he carried out in those two days will have also contributed to the DPGME in the urine, and it cannot be assigned directly to the plate cleaning task.

31

7.1.1.2 Roller Cleaners

The air sample results for the five subjects who carried out Roller Cleaning on the first day were low, ranging from 2.5 to 14 ppm DPGME. The underglove measurements were higher than in the Plate Cleaning being 12-67 µg (Table 7). The urine samples on the first day contained ≤2 mmol.mol-1 pre-shift, but rose to 6 to 14 mmol.mol-1 by the end of the shift.

The air samples for the four subjects on the second day were similar to the first day, 2.5 to 8.5 ppm DPGME. The second-day under-glove Permeatec® measurements were 5 to 370 µg DPGME, much higher than the first day, but the urine samples were no higher than the first day, at 2 to 8 mmol.mol-1.

A further 5 subjects provided urine samples only over the two days, which were analysed for DPGME. They ranged from non-detect to 14 mmol.mol-1.

7.1.1.3 Ink -mixers

The single-use disposable gloves were taped at the cuffs each time to exclude external vapours. The air measurements during the tasks were 19 to 70 ppm of PGME. The underglove measurements were low, 3 to 33 µg PGME (Table 7). Extra measurements made outside the gloves on the forearm and chest were far higher at 26 to 2400 µg PGME (Table 7). The urine samples were accidentally analysed for DPGME with the others, so no PGME results are available.

The underglove measurements are shown in Table 7 and Figure 9 for the first and second days. The amount found on the roller cleaners gloves were higher on the second day than on the first day for all four subjects , indicating that contamination inside the glove had occurred, either from permeation or carried in from repeated re-use.

Table 7 Underglove measurements at Company A from first and second days

Permeatec® Sampler Solvent/Analyte Task Day

No. of results Mean (µg) Std Dev

Underglove Blanco Wash Plate Day 1 6 22.2 7.4 not sealed /DPGME Clean Day 2 0 - -

Underglove Blanco Wash Roller Day 1 22 27.9 19.1 not sealed /DPGME Clean Day 2 11 87.3 116.7

Underglove Ink Mix Day 1 9 13.3 7.1

sealed UltraKing /PGME Day 2 12 10.5 5.7 open to air UltraKing /PGME Ink Mix Day 2 6 674.8 892.8

Gloves used: KCL 743 0.2mm for ink mixing,

Ansell-Edmont 37-675 0.4mm for roller cleaning.

32

0 Pl ix ix

( l ) ( )

µg o

f DPG

M o

r PG

ME

Open Open Sealed Open DPGM PGME PGME

(1570)

PERMEATECS UNDER GLOVE SAMPLERS

-100

100

200

300

400

500

600

700

ate Clean Wash up Ink M Ink MBLANCO WASH not sea ed ULTRAKING Sealed - Open air

1st day

2nd day

DPGM

Figure 9 Underglove measurements at Company A from first and second days

33

8 DISCUSSION

8.1 SUITABLE GLOVES

From permeation tests alone, it is apparent from Table 4 that nitrile gloves of at least 0.38 mm thickness, i.e. the top five entries in Table

RR525 - Use of chemical protective gloves to control ... · gloves are used in the workplace and...

Documents

Transcript of RR525 - Use of chemical protective gloves to control ... · gloves are used in the workplace and...