Occupational Hygiene Peter Simmonds 021-02912826 ...
Transcript of Occupational Hygiene Peter Simmonds 021-02912826 ...
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?