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 History 1917 - 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 assessments Risk 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 5 mg/m 3 Welding fume (not otherwise classified) 3mg/m 3 Zinc Fume 1 mg/m 3 Manganese
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: Welders 1. Welder/Fabricators 2. Trade Assistants 3. Supervisors/Design staff 4.
Structured Risk Assessments Measurements Welding fume – Inhalable particulate sampling train.
Structured Risk Assessment Adjustment for extended shifts Workplace assessments based on eight hour personal measurements. For extended shifts – adjust the welding fume exposure standard
Structured Risk Assessments Results analysis SEG Number in group Welding fume exposures (mg/m 3 ) Welders 2 16 Welders/fabricators 5 8 Trade assistant 4 4 Supervisory/design 3 3
Structured Risk Assessments Statistical analysis 95 th Hazard Number of Average % in excess of Workplace measurements Percentile exposure Exposure standard Standard Welding 7.7 mg/m 3 21 mg/m 3 4 62 5 fume • Occupational exposures are generally log normally distributed. • Use mean for control purposes.
Structured Risk assessments Controls Hierarchy of Controls 1. Elimination 2. Substitution 3. Isolation 4. Engineering controls 5. Administrative controls 6. Personal protective equipment.
Structured Risk Assessments Controls 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 – 214 o C 4. Benzene boiling Point: 80 o C (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 C 9 – 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 As much as the process can be determined, the Company reversed the normal risk assessment procedures. 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
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: Production manager 1. HSE Manager 2. Safety Engineer 3. Occupational Hygienist 4. HSNO - Worksafe NZ 5. Ergonomist 6. Occupational Hygienist Worksafe NZ 7.
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?
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