The practices of workers’ compensation boards are of great importance to employers because employers fund this public insurance regime. How much an employer needs to pay depends on their ‘assessment.’ In determining an employer’s assessment, Québec’s workers compensation board, the Commission de la santé et de la sécurité du travail (CSST), takes into account the risk of employment injuries. This risk can be more significant for some employers than for others. Employers with higher risks pay higher assessments.

Until recently, workers who suffered from lung cancer and who smoked tobacco were rarely compensated by the CSST, even though it was possible that part of their disease had been contracted at work. A recent decision by the worker’s compensation appeal commission, the Commission des lésions professionnelles (CLP), has changed this approach. This may result in increasing assessments for employers.

Previous Practice of the CSST

In order to receive compensation, workers must prove they suffer from an occupational disease. In some cases, the disease will be viewed as a characteristic of the work in question. For example, lung cancer is considered a characteristic of working in the presence of asbestos. If the disease cannot be considered a characteristic of the work, the worker must show the disease is directly related to the risks peculiar to their workplace.

Lung cancer may be caused by multiple factors. Today, tobacco is recognized to be its most dominant cause, but this type of cancer can also result from exposure to carcinogenic elements.

Determining whether the lung cancer of a smoker is due to tobacco or the smoker’s workplace is a difficult task. Cognizant of this fact, the CSST has been very selective in allowing compensation to workers in these circumstances.

When assessing whether lung cancer is directly related to the risks of the work, the CSST used a complex calculation in order to differentiate lung cancers that are probably due to exposure to toxic emanations at work from those that result from smoking tobacco. Basing their judgment on this scientific calculation, the CSST accepted a claim if it was demonstrated that there was a 50 per cent or more chance that the disease was caused by a professional risk such as exposure to carcinogens.

The Alcan Case In Tremblay (Succession de) et Alcan inc., some aluminium workers at Alcan working in the Saguenay-Lac-St-Jean area were exposed to carcinogenic emissions. They were all smokers, and 14 died from lung cancer. Their estates made a claim to the CSST, arguing that the workers had contracted lung cancer at work. The CSST refused the claim. Even if their cancer had two causes (tobacco and the toxic elements at work), the CSST decided that the cancers were probably caused by smoking cigarettes.

The CLP held a different opinion. Although it was not ready to accept that lung cancer was a characteristic of the working conditions in question, it found that the disease was directly related to risks peculiar to the workplace, namely the risk of exposure to carcinogenic emissions.

The CLP noted that workplace conditions do not have to be the dominant cause in order to compensate the worker. It is enough if they contribute in a significant manner to the development or the evolution of the disease. It is necessary to consider whether the importance of the extrinsic cause of the disease (smoking) exceeds the cause of the working conditions in such a way that the working conditions have no significant contribution to the development or the evolution of the disease. This may be the case where the worker is a smoker since, in the CLP’s opinion, tobacco is a "very toxic substance."

The CLP accepted the scientific calculation respecting the cause of cancer, which was used by Alcan and the CSST. However, the CLP did not agree with the weight that should be given to it. The CLP noted that the calculation is a good indicator of the significance of the workplace conditions to the development of the disease, but it is not conclusive. Moreover, the CLP considered that, in order to indicate a significant contribution, the scientific probability that the working conditions caused the disease need only amount to around 25 per cent.

The CLP concluded that tobacco smoking was the main cause of the lung cancer suffered by the workers of Alcan. However, representatives for 10 of the 14 workers had succeeded in proving that working conditions had contributed in a significant manner to the development of the workers’ cancer. As a result, the CLP ordered the CSST to compensate the estates of the 10 workers.

Lessons for Employers

The CSST will likely no longer systematically refuse claims relating to lung cancer only on the basis that the worker is a smoker. Instead, the CSST is likely to compensate smokers who can show their working conditions contributed in a significant way to their lung cancer. This means employers may have increased assessments if their business operates in a field disposed to that type of risk.

However, employers may still be able to avoid paying higher assessments. The law provides a mechanism that may be used to reduce the amount of increased assessment resulting from certain accidents or illnesses. The reduction applies where the employer can show the disease is not entirely attributable to working conditions. In other words, where the employer can demonstrate that the employee has contributed to the development or the evolution of his or her disease, the assessment may be reduced