Occupational Hygiene

Peter Simmonds

021-02912826

prsimmonds@clear.net.nz

My Background

• Scientist with the Ministry of Health at the

National Health Institute (Porirua).

• Worked in consultancies in the UK,

Australia and New Zealand.

• Certified Occupational Hygienist through

the Australian Institute of Occupational

Hygienists and the International

Occupational Hygiene Association.

Outline

1. What is Occupational Hygiene

2. Recent history of the profession

3. Structured Exposure Risk assessments

– the good and not so good

4. Health and Safety by Design

What is Occupational Hygiene

The International Occupational Hygiene

Association (IOHA) defines Occupational Hygiene

as:

'The discipline of anticipating, recognizing,

evaluating and controlling health hazards in the

working environment with the objective of

protecting worker health and well-being and

safeguarding the community at large.'

What is Occupational Hygiene

Where does that name

come from!

“the science that deals

with the preservation

of health”.

Hygeia was the Greek

goddess of health

What is Occupational Hygiene

Aim to eliminate or control occupational

health risks.

We work at the top rather than the bottom of

the cliff.

Recent history

1858 - John Stenhouse introduces a charcoal

impregnated mask to control exposure to gases

and vapours.

Recent History

1890s – Haldane works on the toxicity of carbon monoxide

Exposes rats, mice and even himself to varying concentrations within an “exposure chamber”.

He introduces the use of

canaries to indicate the

presence of toxic gas.

Recent History

First world war, the urgency of the work in munitions factories led to poor

working conditions.

Women filling shells with TNT were nick named the “Canary Girls”. The

TNT turned their skin and pregnant women’s babies yellow. Anaemia

and jaundice resulted in deaths.

Recent History1917 - watch dials began being painted with radium paint.

Women told to “point” brush with their lips to save time.

Began to suffer from anemia,

bone fractures and necrosis of

the jaw, a condition now

known as radium jaw.

1938 – A group of women

successfully sued their

employer and won damages

Recent History

1920s-30s Industrial hygiene develops and

grows in the USA in both the

Public and large private companies.

1938/9 The American Conference of

Governmental Industrial Hygienists

(ACGIH) and the American Industrial

Hygiene Association (AIHA) were formed.

The ACGIH developed the Threshold limit values

(TLV’s) - considered to be health based standards

Recent History

1953 British Occupational Hygiene Society (BOHS)

was formed.

1979 The Australian Institute of Occupational

Hygienists was formed and has around 1000

members.

1994 The New Zealand Occupational Hygiene

Society was formed and currently has around 60

members.

Structured exposure risk assessments

Risk assessment Mantra

Anticipation

Identification

Assessment

Controls

Structured Risk assessments

Case 1:

Construction Steel fabrication industry

Welding fume is the hazard being assessed

Structured Risk assessmentsRisk Identification

1. Welding being undertaken - visual

presence of fume lingering in workplace.

2. Worksafe NZ (DoL) welding assessment

tool

3. Direct reading instruments

4. Safety data sheets (metal and welding

consumable composition)

Structured Exposure assessments

Adverse health effects of welding fume

Mild steel welding – zinc, copper, iron (metal fume fever)

manganese (neurologic effects)

Exposure standards

Welding fume (not otherwise

classified)

5 mg/m3

Zinc Fume 3mg/m3

Manganese 1 mg/m3

Structured Risk Assessments

Similar Exposure Groups (SEG’s)

Definition: A group of employees who have

common risks and similar exposures.

For a construction steel fabrication plant they maybe:

1. Welders

2. Welder/Fabricators

3. Trade Assistants

4. Supervisors/Design staff

Structured Risk AssessmentsMeasurements

Welding fume– Inhalable particulate sampling train.

Structured Risk AssessmentAdjustment for extended shifts

Workplace assessments based on eight hour personal measurements.

For extended shifts – adjust the welding fume exposure standard

Structured Risk AssessmentsResults analysis

SEG Number in group Welding fume

exposures

(mg/m3)

Welders 2 16

Welders/fabricators 5 8

Trade assistant 4 4

Supervisory/design 3 3

Structured Risk AssessmentsStatistical analysis

Hazard Number of

measurements

Average 95th

Percentile

% in excess of

exposure

standard

Workplace

Exposure

Standard

Welding

fume4 7.7 mg/m3 21 mg/m3 62 5

•Occupational exposures are generally log normally

distributed.

•Use mean for control purposes.

Structured Risk assessmentsControls

Hierarchy of Controls

1. Elimination

2. Substitution

3. Isolation

4. Engineering controls

5. Administrative controls

6. Personal protective equipment.

Structured Risk AssessmentsControls

1. Immediate controls would be a minimum of P2 respiratory

protection.

2. Training, fit testing of masks, lung function testing

3. Portable or fixed exhaust ventilation systems

Structured Risk Assessment

Ongoing issues with controls

Compliance with the use of PPE

Extraction systems not being used

Extraction systems don’t reach the weld area.

Structured Risk Assessment

Case Study 1 – Summary

1. Presence of a hazard identified

2. Worker welding fume exposures assessed

3. Appropriate controls put in place

Not so structured risk assessment

Case Study 2

Nickel mine builds a plant to separate cobalt

and nickel from the refined ore.

Plant is a flotation system using a solvent in

the process.

Not so structured risk assessment

Site is concerned that benzene is present in the

solvent.

Undertakes biological monitoring for benzene

metabolites in urine ( t,t muconic acid and

S-phenyl mercapturic acid).

Benzene metabolites identified in operators

urine samples, some approach the

Biological Exposure Index level (BEI)

Not so structured risk assessment

Solvent used is Shellsol A150:

Information from the safety data sheet:

1. Solvent naphtha (petroleum), heavy

aromatic

2. Hazardous Chemicals – Naphthalene and

tri methyl benzenes

3. Boiling point range: 180 – 214oC

4. Benzene boiling Point: 80oC (not on SDS)

Not so structured risk assessment

Contract a Occupational Hygiene Consultancy

to undertake an extensive solvent

monitoring programme

Interim monitoring report

44 personal and 77 area samples - small

amounts of C9 – C12 hydrocarbons (tri

methyl benzenes and naphthalene)

Not so structured risk assessment

NO BENZENE DETECTED IN ANY OF

THE AIR SAMPLES

Not so structured risk assessment

ANY IDEAS!

Not so structured risk assessment

Benzene a component of cigarette smoke

Highest biological monitoring results

correlated with the heavy smokers

Not so structured risk assessment

What went wrong?

Not so structured risk assessment

Control Biological monitoring is a control used

to monitor the effectiveness of your

controls – no baseline monitoring

Assessment Rigorous assessment

Identification Cigarette smoke contains benzene

As much as the process can be determined, the Company

reversed the normal risk assessment procedures.

Health and Safety by Design

Recently involved in a Health and Safety by

design project.

New build powder coating plant

Health and Safety by Design

Involved professions:

1. Production manager

2. HSE Manager

3. Safety Engineer

4. Occupational Hygienist

5. HSNO - Worksafe NZ

6. Ergonomist

7. Occupational Hygienist Worksafe NZ

Health and Safety by Design

Involved two one day meetings

Initial “brain storming” meeting

Second meeting - divided into groups and

final all members meeting.

Health and Safety by Design

Some great ideas were generated during the

meetings.

The plant is still under construction.

Proof will be in the pudding!

Any Questions?