Leveraging environmental reporting databases to assess occupational and environmental exposures

Project Overview

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An estimated 7 to 19% of cancers are currently attributable to toxic environmental and occupational exposures. One of several primary prevention policy approaches is toxics use reduction, which aims to promote changes in industrial and manufacturing processes to reduce the use and release of toxic chemicals. The goal of toxics use reduction is to reduce, substitute or eliminate the use and release of hazardous industrial pollutants by altering industry production processes, redesigning products and systems and rewarding innovative industries for using less hazardous chemicals. In 2010, Ontario took the lead in Canada and implemented the Toxics Reduction Act (Reg. 455/09). Ontario’s Toxics Reduction Act will be repealed on December 31, 2021.

Until it is repealed at the end of 2021, Ontario’s Toxics Reduction Act (TRA) requires four major manufacturing and mineral processing industrial groups, which already report their releases of pollutants to the federal National Pollutant Release Inventory (NPRI), to additionally track and report their annual use, creation and release of prescribed toxic substances to the Ontario Ministry of Environment and Climate Change. These datasets are publically available online on the Ministry’s website.

The TRA was modelled after the Massachusetts Toxic Use Reduction Act of 1989 (TURA), which has reported significant declines in carcinogen use and releases, including for example the decline in the use and release of lung carcinogens by 31% and 77%, respectively. Massachusetts has also reported economic benefits and technological advances in manufacturing, utilities and other sectors.


This project has two main goals, namely:

  1. To evaluate the performance of the Ontario Toxics Reduction Act (TRA). The TRA encourages industrial facilities in the province to reduce their use, creation and release of prescribed toxic substances and submit annual reports to the Ministry of Environment and Climate Change. Specifically, we aim to:
    • Analyze data from the existing TRA database and report trends in use, creation and releases of contaminants in air. Some of the data collected under the TRA include: the quantity of each toxic substance used, created, emitted, discharged, spilled, or recycled.
    • Analyze emissions data from the National Pollutant Release Inventory (NPRI) database. The NPRI collects both on-site and off-site pollutant release and transfer information for all industrial facilities in Canada. The analysis of NPRI data for the companies covered by the TRA before and after the passage of Ontario’s TRA allows for the evaluation of TRA.
    • Review efforts proposed or taken to reduce releases by analyzing information contained in electronic reports submitted by industries regulated under Ontario’s TRA. The reports highlight any process changes and detailed reduction plans for each toxic substance.
  2. To explore the feasibility of using data from the TRA and NPRI databases as a surveillance tool for occupational and environmental exposures.
    • Evaluate the quantity of carcinogens used and emitted by industries in Ontario and apply these variables as indicators of potential occupational and environmental exposure.
    • Explore the use of geographic profiles to summarize regional trends from employment data and industrial chemical use data.
    • Explore potential applications of the TRA data for occupational exposure surveillance.

Data from 2011 to 2015 were downloaded and substances were identified by their name and chemical abstract service (CAS) number. The datasets also contain facility-level information on the number of workers employed, the facility’s industry sector code and its geographic location. The datasets were analyzed to examine industrial use and emission trends by sector, region and carcinogen type.


Two studies using data from the TRA have been completed which assessed trends in the use and emission of carcinogens by carcinogen type as well as by sector and geographic location. We also highlight the industrial use of particular carcinogens to indicate potential occupational exposures for setting cancer prevention priorities in Ontario Health’s 2020 report on the Prevention System Quality Index. The OCRC has also assessed the feasibility of using data from the TRA to establish an occupational exposure surveillance system.


The TRA allows us to follow trends in the use and emission of toxic chemicals, and discern where reductions are needed to prevent potential occupational and environmental exposures. The results of this study highlight the importance of maintaining the TRA in Ontario as an ongoing tool for exposure surveillance.

Progress (updated March 2021)

Ontario announced in 2019 that it would repeal its Toxics Reduction Act (TRA) on December 31, 2021 in an effort to avoid unnecessary duplication with the federal government’s Chemicals Management Plan. We continue to analyze trends in the industrial use and emission of toxic substances using data from the NPRI.

Research Team
Cathy Slavik
OCRC, McMaster University
Sheila Kalenge
Paul A Demers
OCRC, University of Toronto