The City of Toronto’s Cured in Place Pipe (CIPP) sewer relining process involves the use a plastic resin to create a new pipe inside of an existing pipe. This process allows for the repair of sewer pipes without extensive excavation that can be disruptive to local communities and businesses.
Amongst other components, CIPP uses a resin that contains a substance called styrene. When heated, styrene has a very distinctive smell, which some have described as a strong bitter sweet smell. The smell can be detected in the air at concentrations as low as 0.016 parts per million (ppm) – much lower than the applicable occupational and health benchmarks.
Some residents have requested information on the potential health impact from exposure to styrene used in CIPP.
Based on the review of available information, with details found below, Toronto Public Health concludes that exposure to styrene used in CIPP is unlikely to result in adverse health effects.
Styrene is a clear, colourless liquid that is commonly used in the production of many everyday products such as plastic packaging, counter tops, disposable cups and containers, insulation and others. Styrene is also produced naturally by some plants. We are constantly exposed to small amounts of styrene in both ambient and indoor air, mostly attributable to emissions from building materials, and consumer products.
In Ontario, the Occupational Health and Safety Act sets the occupational exposure limit for styrene at 35 ppm. The short term exposure limit for the general public is 5 ppm.
In a study conducted for Toronto Works and Emergency Services the highest levels of styrene measured in homes during CIPP work ranged between 0.1 and 0.2 ppm – far below the applicable occupational and health benchmarks.
Based on this information, Toronto Public Health concludes that CIPP work is unlikely to result in adverse health effects.