Workers Health & Safety Centre

Many Canadian workers are overexposed to solar UVR, study finds

Exposure to solar ultraviolet radiation (UVR) is one of the most common causes of occupational cancer, yet it has been inadequately addressed by researchers and regulators alike. 

Few have also objectively measured worker exposures to solar UVR on the job. However, new Canadian research has set out to help fill these gaps.

The research and findings

A recent study led by Dr. Cheryl Peters, research scientist, Cancer Epidemiology and Prevention Research, Alberta Health Services, Cancer Control Alberta found: 
  • The average UVR dose of study participants was almost 5 times the recommended limit
  • 10 per cent of workers studied were exposed at more than 10 times the limit
  • Utility workers had double of exposure of municipal workers
  • Ontario workers had the greatest average UVR exposures, likely because participating utility workers, who had the highest levels of UVR exposure, were all from Ontario.

To arrive at these findings, workers from 13 different workplaces in British Columbia, Ontario and Nova Scotia participated in an exposure monitoring campaign (late summer/early fall 2016). Participants, who worked for power utilities or municipalities, wore a UVR measurement badge on either their wrist, shoulder or hardhat. The UVR doses were compared with the internationally recommended exposure limit of 1.3 SED (standard erythemal dose).

Wider initiative

This latest study was conducted as part of the larger Sun Safety at Work Canada (SSAWC) project, funded by the Canadian Partnership Against Cancer’s CLASP program (Coalitions Linking Action and Science for Prevention). The SSAWC project raises awareness of sun safety and the need for workplace prevention programs through its dedicated web site and a compilation of best practices from Canada and abroad.
The study also builds on 2012 research, also led by Peters. It concluded some 1.5 million Canadian workers are exposed to solar UVR at work, with three-quarters of workers highly exposed during their work (being outdoors more than 75 per cent of the workday). The largest at risk occupational groups were farmers, construction labourers, and landscapers but others at increased risk are those employed in parks and recreation, mining, forestry and logging.  

Since 1992, Solar UVR has been classified by the International Agency for Research on Cancer as a known human carcinogen that causes skin cancer. Other studies have linked solar UVR with melanoma of the eye and possibly non-Hodgkin lymphoma. In Ontario, the estimated incidence of occupational cancer caused by solar UVR is high. The Burden of Occupational Cancer in Ontario report found some 450,000 Ontario workers are exposed each year, causing an approximately 1,400 non-melanoma skin cancer (NMSC) cases.

Other researchers have calculated the economic burden of occupational NMSC due to solar radiation in Canada. They estimate some 4,500 new cases of work-related NMSC each year, costing $28.9 million a year in direct and indirect costs.  

Need for action 

In Canada, there are no specific legislated occupational exposure limits (OEL) for solar UVR. Ontario’s Ministry of Labour offers guidance on the prevention of overexposure to UVR at work. They say they apply the threshold limit values (TLVs) recommended by the American Conference of Government Industrial Hygienists for occupational exposure to sources of UV radiation. To enforce these TLVs they refer to the Occupational Health & Safety Act’s employer general duty clause (25(2)(h)) to take every reasonable precaution for the protection of workers. As this latest research (and the 2012 study) shows though, recommended OELs for solar UVR are routinely exceeded.
Cancer prevention advocates recommend workplaces develop and implement a specific sun safety program that should include:  
  • A hazard assessment to identify worker exposures;
  • Sun protection control measures (eg. Design and use of shade structures to maximize UVR protection during work and breaks; scheduling tasks to minimize the time spent working outdoors during peak UV hours from 11 a.m. to 3 p.m.; tinting windows on vehicles) and
  • Sun protection training to increase awareness and help prevent solar UVR exposures.  

Research on the impacts of the climate crisis on worker health and safety suggest worker exposures may increase over time. If the climate crisis goes unaddressed, the need for greater worker protection will become even more urgent. Regardless, with current worker exposures now measured at five and 10 times the recommended limit, clearly the need for action is also now. 

Related resources
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WHSC offers a wide range of training programs and resources, including a related hazard bulletin on Heat Stress. All of these support workplace efforts to identify and address work-related hazardous exposures and their prevention.

To learn more:
Call:   1-888-869-7950 and ask to speak with a training services representative