Occupational exposure assessment: Why you need an industrial hygienist OEMAC Conference Montreal, September 29, 2013 Jan-Erik Deadman, PhD Corporate health and safety advisor Learning objectives • Recognize the importance of assessing the right route of exposure • Recognize the importance of correctly understanding the reference standard • Be more critical of exposure assessments • Recognize the central role of the industrial hygienist in the management of occupational health risks 2 Vice-présidence – Ressources humaines, Hydro-Québec Plan • Exposure assessment : – Central to occupational health – The process in detail – Interactions with the occupational health team, managers and workers – From perception to reality – Proactive exposure assessment – Reactive exposure assessment • Conclusions 3 Vice-présidence – Ressources humaines, Hydro-Québec 1 Exposure assessment "How important is this exposure?" "Does it represent a risk to health?" "Does it need to be reduced, and if so, how should it be done?" • The answers to these questions are found in one of the most important functions performed by the industrial hygienist : exposure assessment. 4 Vice-présidence – Ressources humaines, Hydro-Québec Exposure assessment : What is it? • The process of estimating the magnitude of exposure to an agent and describing its sources, pathways and the uncertainties of the estimate • Includes comparison with a reference value • Two fundamental goals – identify determinants of exposure (factors that modify exposures) – identify risk to the health of exposed individuals • Relies on observation, documentation and tools to evaluate a situation in the workplace – Observation • vision, hearing, olfaction & 6th sense – Documents • Ex., reference values, engineering plans / process flow charts • material safety data sheets, published reports – Tools • Ex., equipment to measure concentration or level of exposure • video camera, air velocity meter, smoke generator 5 Vice-présidence – Ressources humaines, Hydro-Québec Exposure assessment : Central to occupational health Identify exposure to hazards Identify undesirable effects Identify tolerance levels Exposure / risk (standards : legal, health, assessment comfort, best practices) Evaluate exposure and risk Risk management Identify appropriate control measures Risk control Implement control measures Evaluate effectiveness 6 Vice-présidence – Ressources humaines, Hydro-Québec 2 Exposure assessment : Central to occupational health Risk Education & communication training Exposure assessment Controls Situation acceptable? Personal Engineering - Legal standards protective - Health-based standards Administrative equipment Yes - Comfort standards No Work practice (Negative exposure (Positive exposure determination) determination) Epidemiological surveillance Compliance monitoring Medical surveillance 7 Vice-présidence – Ressources humaines, Hydro-Québec Exposure assessment : The process • What is the hygienist looking for? – Opportunities for exposure – Interactions between workers, raw materials, equipment and control measures that result in exposure to an agent at an undesirable level • How does the hygienist do this? – Understanding : • Operations and tasks that constitute the processes • Physical, chemical and mechanical principles at work • Worker's habits • Effectiveness of control measures • Reference values (tolerance limits) – Attentive observation of the work situation : • People, equipment, organisation of activities 8 Vice-présidence – Ressources humaines, Hydro-Québec Exposure assessment : The process • Break down of activities into their basic steps • Identification of raw materials, intermediates, final products, equipment, machinery and control measures used at each 2 step: 1 – form, quantity, composition of materials – intrinsic toxicity – propensity to be released into the air – relative importance of the quantity 4 released 3 9 Vice-présidence – Ressources humaines, Hydro-Québec 3 Exposure assessment : Understanding the reference value • Once exposure is adequately assessed, with what do we compare it ? • Is there a relevant reference value? • For what (and whom) was it developed ? : – which health effects? – chronic, acute, or sub-chronic? – which reference population? – which route(s) of exposure? • What are the uncertainties? – "nearly all workers" 10 Vice-présidence – Ressources humaines, Hydro-Québec Interactions : It's teamwork ! • The industrial hygienist acts as the interface between the different occupational health experts : • Safety officer / engineer • Industrial hygiene technician • Occupational physician / occupational health nurse • Ergonomist • Occupational psychologist • … between the different workplace experts : • Worker (expert in work actually performed) • Engineer / process designer (expert in work as designed) • Manager (in between the above two…) • … and with external agencies : • Analytical laboratory • Consultants • Regulatory agencies • Media 11 Vice-présidence – Ressources humaines, Hydro-Québec Exposure assessment : Interactions with OH professionals • The occupational hygienist's strong suit : identify, quantify, and Epidemiological propose solutions for exposures surveillance that present chronic risks • Adequate exposure assessment allows better focussing of : – medical surveillance – epidemiological surveillance Medical surveillance 12 Vice-présidence – Ressources humaines, Hydro-Québec 4 Exposure assessment : Interactions with workers / management • Adequate exposure assessment also allows risk communication and training to be geared to actual (and not hypothetical) exposure levels 13 Vice-présidence – Ressources humaines, Hydro-Québec Exposure assessment : Interactions with management, engineering and workers • Adequate exposure assessment also allows : – Better tracking of exposure trends – Better focussing of engineering, administrative or work practice controls – Appropriate selection and use of PPE 14 Vice-présidence – Ressources humaines, Hydro-Québec Exposure assessment : proactive and reactive Proactive (cause → consequence) : • Does a particular occupational situation present a risk to health ? Reactive (consequence → cause) : • Can the observed or alleged health effects be related to an exposure in the workplace ? 15 Vice-présidence – Ressources humaines, Hydro-Québec 5 Exposure assessment – from perception to reality … risk perceived by the process designer … risk perceived by the worker http://www.pgbeautyscience.com/assets/images/safety/risk-hazard-exposure.jpg 16 Vice-présidence – Ressources humaines, Hydro-Québec Exposure assessment – from perception to reality • Risk evaluation by an occupational hygiene professional Intrinsic toxicity x Route of exposure - Preventive = Risk measures Frequency Duration Comparison with tolerance level 17 Vice-présidence – Ressources humaines, Hydro-Québec Exposure assessment – from perception to reality • Does this mean that we should disregard perception? – Absolutely not ! • The goal is to align perceptions with objective risk assessment 18 Vice-présidence – Ressources humaines, Hydro-Québec 6 Proactive exposure assessment Example : Prevention of health risks from exposure to lead • Hydro-Québec's objective : establish best practices to manage lead exposure and prevent health risks • Guide for preventing risks to health from lead exposure 1. Identify activity and the expected risk category 2. Identify corresponding preventive measures 3. Inform workers about the effects of lead on health and preventive measures 4. Implement preventive measures, including a respiratory protection program 5. Monitor the implementation of preventive measures in the field 6. If necessary, monitor concentration of lead in air and surface contamination 7. Institute biological monitoring if indicated. 19 Vice-présidence – Ressources humaines, Hydro-Québec Proactive exposure assessment Example : Prevention of health risks from exposure to lead 20 Vice-présidence – Ressources humaines, Hydro-Québec Proactive exposure assessment Example : Prevention of health risks from exposure to lead Low risk (< 50 ug/m3) Moderate risk (50 - 500 ug/m3) High risk (500 - 2500 ug/m3) Very high risk (> 2500 ug/m3) 21 Vice-présidence – Ressources humaines, Hydro-Québec 7 Reactive exposure assessment : Lead on surfaces 22 Vice-présidence – Ressources humaines, Hydro-Québec Reactive exposure assessment : Lead on surfaces • Hydroelectric generating station built in 1942 - 1945 • 48 MW • 4 Francis turbines • 15 employees • Overhaul of generating units • Anticorrosive lead- based paint used on many surfaces 23 Vice-présidence – Ressources humaines, Hydro-Québec Reactive exposure assessment : Lead on surfaces 24 Vice-présidence – Ressources humaines, Hydro-Québec 8 Reactive exposure assessment : Lead on surfaces Inside surface of spiral casing 25 Vice-présidence – Ressources humaines, Hydro-Québec Reactive exposure assessment : Lead on surfaces Lead identified on multiple surfaces by contractor • Lead present in paint (0,2 % to 8,7 %) • Hydro-Québec's objective : prevent health risks from lead exposure • Contractor's objective : establish level of contamination before renovation work – Wipe sampling conducted by contractor to determine presence and extent of any surface contamination – Reference value used by contractor and industrial hygiene consultant • 11 µg / 100 cm2 – Results for surfaces (values expressed in µg / 100 cm2) • 23 wipe samples • < 11 µg / 100 cm2: 7 samples • > 11 µg / 100 cm2: 16 samples (up to 3,030 µg / 100 cm2) 26 Vice-présidence