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Is your work environment making your employees sick? How to reduce the risk of Occupational Cancer


Is your work environment making you sick? How to reduce the risk of Occupational Cancer

Every day, workers in Ontario are exposed to a wide range of known and suspected carcinogens. Approximately 3000 cancers diagnosed each year in Ontario are due to exposure in the workplace. Despite knowing about these occupational cancers, we often don’t pay close attention to what may be in the air around while people are working.  “A traumatic injury from getting caught in machinery is immediate. The latency period for occupational cancer can be very long, often years or decades later,” explains Jessica Major, a Specialized Consultant in Occupational Hygiene with WSPS. “The effects of exposure may not be obvious right away,” she says.

In 2020, a study done by the Occupational Cancer Research Centre identified sixteen carcinogens that contribute to occupational cancers. Ultraviolet radiation from working outdoors is at the top of the list. Asbestos, crystalline silica, diesel exhaust, welding fumes, hexavalent chromium, radon, and benzene were also high on the list. “Sometimes the link between a specific exposure and the development of cancer in a worker is difficult to confirm; however, in some cases, the link is well established,” says Jessica.  

Many of these substances are found in building materials, so those working in the construction industry may face exposure to carcinogens. The processes used in manufacturing settings, especially where welding is involved, also produce some of these carcinogens. “The most common types of occupational cancer are lung, skin, and bladder cancers,” says Jessica. “With most of these, the carcinogen is inhaled into your lungs, leading to lung cancer. Skin cancer from sun exposure is the most prominent. Benzene exposure can lead to leukemia and multiple myeloma. And then diesel exhaust is linked to bladder cancer.”

“Another consideration is the presence of multiple exposures, where the risk becomes even greater,” says Jessica. She provides the example of smoking. When cigarette smoke is inhaled along with asbestos or silica, for example, the risk of developing cancer becomes much greater. “In these cases, one plus one doesn’t equal two. It may equal ten.” 

Protect employees

Apply the hierarchy of controls. “If a substance is carcinogenic, eliminate it if possible. Look for a substitute,” advised Jessica. When a substitute is not possible due to the specific properties of a chemical or process, Jessica recommends a combination of engineering controls and PPE for workers. For example, a local exhaust ventilation system and appropriate respirators. Administrative controls can be effective as well, such as routinely rotating or repositioning workers to limit their exposure. Jessica still recommends PPE in addition to administrative controls. 

Follow the occupational exposure limits (OELs) outlined in Ontario Regulation 833. This regulation provides the acceptable amount of exposure for identified substances in a specified timeframe. Use the extended table to get more complete information about a substance. Have a qualified person or a third party conduct a risk assessment to determine which substances may be in the workplace. Then, have a qualified person complete air sampling to get accurate measurements.  

Ensure employees complete site-specific WHMIS training. Standard WHMIS training is obviously important, but when you’re dealing with carcinogenic substances, site-specific training is crucial. All workers must be aware of the substances that they will encounter during the course of their work. They also need to be familiar with the Safety Data Sheet (SDS) for each one. “The SDS will indicate the health risks of the substance and will also list recommended controls,” says Jessica. “Employers must know this information in detail, ensure the necessary processes and controls are established, and communicate the information to employees via training so that they understand why it’s important to follow the established processes.”

How WSPS can help 


Connect with a WSPS Occupational Hygiene Consultant to find out more about the services they can provide. 


WHMIS 2015  (eCourse, 1 hour) 

Airborne Chemical Exposure Assessments Awareness (eCourse, 1.5 hours) 


Workbook for Designated Substance Assessments 

MLITSD Healthy Worker Healthy Workplace Initiative: Silica Exposure (video) 

Protecting Against Respiratory Hazards 

Occupational Hygiene (article) 

How can employers test their workplace’s indoor air quality? (video)  

Quick Safety Tips: Designated Substances (video)  

• Source Material: OCRC Report: Using Scientific Evidence and Principles To Help Determine the Work-Relatedness Of Cancer