OHS Canada Magazine

Occupational hygiene holds important place within profession

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October 9, 2020
By Richard Quenneville

Occupational Hygiene editor pick Occupational Hygiene

Occupational hygienists focus on hazards that may not have immediate outcomes, but may lead to serious consequences

Simply put, occupational hygiene is ‘the science devoted to preventing illness from work activities.’ (freeman98589/Adobe Stock)

The American Board of Industrial Hygiene (ABIH) — now known as the Board for Global EHS Credentialing (BGC) — reported that at the end of last year, there were 6,940 certified industrial hygienists (CIH) globally, of which 6,225 were in the United States.

Canada has the second largest group of ABIH diplomates (448) followed by China (92), Singapore (37), Hong Kong (34), India (30), Australia (30), South Korea (15), Malaysia (13), Taiwan and Saudi Arabia (eight each).

The Canadian Registration Board of Occupational Hygienists (CRBOH) is our national organization responsible for certifying registered occupational hygienists (ROH) and registered occupational hygiene technologists (ROHT) in Canada.   

At the June 11 annual general meeting, CRBOH reported that there were 316 ROH and ROHTs active members.   

These credentials (ROH, ROHT and CIH) certify that the individuals delivering occupational hygiene services in Canada have undergone a critical review of their years of occupational hygiene work experience, have the required science or engineering education, and have successfully passed written and oral exams designed to test their knowledge and certify that they are professionals.   


With such a small group of certified professionals in Canada, the general public may not necessarily know what occupational hygiene is.

Science of safety

The term occupational hygiene (used in Canada, the United Kingdom and Commonwealth countries, as well as much of Europe) is synonymous with industrial hygiene (used in the U.S., Latin America, and other countries that have received initial technical support or training from U.S. sources).

Occupational hygiene is often defined as the science devoted to the anticipation, recognition, evaluation, prevention and control of those environmental factors or stresses (stressors) arising in or from the workplace which may cause sickness, impaired health and well-being, or significant discomfort among workers or citizens of the community.

In simple terms, occupational hygiene is “the science devoted to preventing illness from work activities.”

Occupational hygienists are scientists and engineers committed to protecting the health and safety of people in the workplace and the community.

Old-school (long-standing) occupational hygienists — including myself — originally rose from careers in the sciences, such as chemistry, biology, physics or engineering. We were self-trained on the job, attended many training courses and eventually had the courage, confidence and aptitude to challenge the certification exams and be designated a professional occupational hygienist.

That approach, of course, has evolved.   

Canada now has four universities — the University of Toronto, McGill University, University of Montreal and University of British Columbia — that offer master’s degree programs which provide the necessary education and foundation to become a professional occupational hygienist, or pursue designation as such.

Complimenting OH&S

Occupational safety may be defined as the maintenance of a working environment relatively free from actual or potential hazards capable of causing physical harm to those who work in the environment.

Safety professionals are typically responsible for monitoring and managing workplace safety and developing programs in order to help senior management comply with occupational health and safety legislation and prevent accidents in the workplace.   

Occupational safety professionals often focus on workplace physical safety issues that can cause immediate injury or death such as hazardous work, slips and trips and falls, logout or tagout protocols for hazardous machines, hazardous energies, workplace violence, loss time accidents, safety inspections and risk management.

Occupational hygienists, by comparison, focus more on workplace hazards that may not have immediate outcomes, but may also lead to serious consequences, such as occupational illness, a shortened lifespan or quality of life.

Occupational hygiene compliments the health and safety process by providing expert evaluation and anticipation of the significant exposure routes for chemical, physical or biological exposures, based on their physical or chemical properties.   

Occupational hygienists can characterize important similar exposure groups in a workplace in order to prioritize limited sampling resources and budgets on high-risk workers and avoid waste.   

Occupational hygienists advise on sampling strategies to ensure sufficient samples are collected to statistically model the worst-case occupational exposure(s) in a similar exposure group and identify the risk of overexposure or even model workplace exposures.

Workplace evaluation

Practically speaking, occupational hygienists may not spend much time evaluating workplace physical safety or accident statistics. However, they do spend a lot of time evaluating and analyzing occupational hygiene issues that exhibit the potential for causing serious illness.

These may include biological agents such as allergens, mould, endotoxins or even COVID-19. Occupational hygienists are trained and experienced in evaluating  hazardous properties of chemical agents in the workplace, such as acute toxicity, skin corrosion and irritation, eye damage and irritation, respiratory and skin sensitization, genotoxicity, carcinogenicity, reproductive toxicity and specific organ toxicity — and identify high-risk agents and provide recommendations based on the hierarchy of controls.   

Occupational hygienists can evaluate workplaces over exposure to heat stress and strain from machines, clothing choices and work intensity, assess chemical risks in a confined space and identify significant factors for improving poor indoor air quality.

They are also able to assist OH&S professionals in evaluating ergonomic factors in the workplace that may affect worker health through repetitive motion, awkward postures, poor lighting or unacceptable loads during manual material handling.

Occupational hygienists are experts in evaluation of workplace exposures to physical agents such as ionizing and non-ionizing radiation, lasers, noise and vibration and are able to enhance the health and safety process in the workplace.   

They can advise and develop programs for personal protective equipment, including respiratory protection, cartridge change-out schedules and suitability of skin protection based on chemical permeability. They can recognize ventilation problems and make recommendations for improvement.

Based on the certification maintenance requirements for CIH, ROH and ROHT, occupational hygienists and technologists are required to attend courses, deliver training at conferences, participate in occupational hygiene associations — in addition to their practice, in order to maintain their certifications.   

This results in professional occupational hygienists being current in new technologies such as advanced manufacturing techniques like 3D printing, nanotechnology, statistical analysis and emerging occupational hazards.

Occupational hygiene is a specialty science and necessary in the health and safety process to collaborate with and advise safety professionals on how to evaluate workplace agents capable of causing occupational illness.

In order to ensure that you are using a qualified occupational hygiene professional, contact the Canadian Registration Board of Occupational Hygiene or the American Board of Industrial Hygiene to see if they are on the roster.

Richard Quenneville is the senior director of corporate services with T. Harris Environmental Management in Toronto.

This commentary appears in the September/October 2020 issue of OHS Canada.


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