What is categorization?

Chemical substances have been used in Canada for decades - some for hundreds of years. As a common part of everyday life, chemical substances can be a by-product of other processes, be deliberately created, or occur naturally in the environment.

Industry and other organizations use chemical substances for research, developing new products, and in the production of the many consumer products we use. 

Like many countries, Canada's laws say companies must submit their new chemical substances for scientific assessment before they can be manufactured or imported. 

However, many chemical substances have been used for much longer than these laws have been in place. Although some older, "existing" ones have been examined by environmental and health scientists in government, many have not.

Categorization was required by the Canadian Environmental Protection Act, 1999 (CEPA 1999) and is a first step to finding out which of these chemical substances require further attention in the form of assessment, research and/or measures to control their use or release.  

Categorization of the Domestic Substances List

The definition for a "substance" in CEPA 1999 is very broad. It includes any kind of matter that could be used or released into the environment.

More than 23,000 chemical substances were in use in Canada between January 1, 1984 and December 31, 1986, when the original CEPA was being created. The law calls these "existing substances," and they are registered on the Domestic Substances List (DSL).

CEPA 1999 set a goal for the Government of Canada to sort through or "categorize" all 23,000 chemical substances. This task was completed by September 2006, as required by the Act.

Using information from Canadian industry, academic research and other countries, Government of Canada scientists worked with partners in applying a set of rigorous tools to the 23,000 chemical substances on the DSL. They were categorized to identify those that were:

• inherently toxic to humans or to the environment and that might be:
  • persistent (take a very long time to break down), and/or
  • bioaccumulative (collect in living organisms and end up in the food chain)
• substances to which people might have greatest potential for exposure.

Many industrialized countries around the world are undertaking a similar process. Most, however, focus only on chemicals that are used on a very large scale.  In 2006, Canada became the first to complete categorization.  There were approximately 4,000 chemical substances identified as needing further attention. Click here for the results of categorization.

Moving Forward

Categorization is the first step in scientifically assessing chemical substances on the DSL. 

The chemical substances identified as needing a more thorough examination have also been sorted to ensure those with the greatest potential for concern are examined first.

The chart shows how the Government of Canada completed categorization.  The next step for the chemical substances requiring further attention includes screening assessment, research and if needed, measures to control the use or release of a chemical substance. These actions may also determine that there is no risk to human health and the environment.

Categorization has added a great deal to what we know. This information will be helpful in the future.  Before categorization was finished, we had knowledge on a small set of chemical substances. Now, we have a baseline of important information for all chemical substances to help guide decisions for years to come. Information from categorization will be available to everyone in Canada, including those who need to assess risks and make decisions about managing and using chemical substances.