Occupational Disease


Occupational diseases are caused by exposure to physical, chemical, or biological agents in the workplace. This chapter provides an overview of both Schedule 1 and Schedule 2 occupational disease claims that were registered and allowed by the WSIB over the past 10 years. Between 2009 and 2018, the WSIB allowed about 134,000 occupational disease claims which made up over $920 million in benefit costs*. Occupational disease claims are grouped into four major categories: long latency illnesses, noise induced hearing loss, chronic exposures and effects, and acute exposures and effects.

*Benefit costs represent the life-to-date costs associated with the claim as of March 31, 2019.


Long latency illness claims

Many occupational diseases do not develop until a long time after the harmful exposure took place. In long latency illnesses sometimes the symptoms may not show up until many years after being exposed to a disease causing agent. While these claims were only three per cent of all allowed occupational diseases registered at the WSIB between 2009 and 2018, they include some of the most serious illnesses and make up the largest amount of allowed benefit costs. One example is mesothelioma, which is a cancer of the pleura or peritoneum that can develop from exposure to asbestos decades ago.

The five leading diagnoses are pleural plaques, mesothelioma, lung cancer, asbestosis, and prostate cancer, which make up 66 per cent of all allowed long latency illness claims over the past 10 years.


The five sectors with the most claims are Schedule 2, construction, manufacturing, municipal, and primary metals. 27 per cent of allowed long latency claims come from Schedule 2.

Noise induced hearing loss claims

Noise induced hearing loss (NIHL) is a permanent loss of hearing, usually in both ears, resulting from inner ear damage due to prolonged, continuous, or intermittent hazardous noise exposure. This type of hearing loss is a cumulative process that develops over many years. As a result, noise induced hearing loss often does not become apparent until people are older and often retired from the workforce.

Allowed noise induced hearing loss claims registered between 2008 and 2017 accounted for about 24 per cent of all allowed occupational disease claims. The top five sectors for allowed noise induced hearing loss claims over the last 10 years are: manufacturing, construction, Schedule 2, services, and transportation.

Claims for chronic exposures and effects

Occupational diseases in this category involve medical conditions that develop gradually over time from prolonged or chronic exposures in the workplace. Symptoms often have a temporal association with workplace exposures; the disease often becomes apparent while the individual is still working in the exposure environment.

Chronic exposures can occur through inhalation or skin absorption. Conditions like dermatitis and some respiratory diseases can be caused by chronic exposure to chemical or biological agents in the workplace. Allergy to latex is an example of a condition that can develop in workers exposed to that agent in the workplace. Dermatitis claims make up 44 per cent of allowed chronic exposures and effects cases.


Claims for acute exposures and effects

Acute exposures and effects describe medical conditions that happen right after the person is exposed to a chemical, biological or physical agent at work. Between 2009 and 2018, these claims were 61 per cent of allowed occupational disease claims while having the lowest benefit costs. Exposures to infectious disease from getting bit or being stuck by a needle make up most of these claims.

In the last 10 years, the Health care sector and Schedule 2 had the highest number of these claims, and made up 66 per cent of claims in this category.