What is Risk assessment?
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Chemical substances have many different properties and many different uses. Some are used to make plastics flexible, some put out fires quickly and efficiently, some are products of common chemical reactions that occur naturally in the environment (such as a volcanic eruption) - still others form part of our day-to-day activities, such as driving a car.
 In the same way that chemical substances have different uses, they can also be harmful in different ways. For instance, some may harm plants, while some may cause very serious illnesses in people such as cancer. Still others may be carried long distances through the air and affect people far away.
The risk posed by a chemical substance is determined by its hazardous properties and how or where exposure takes place. A scientific evaluation, or "risk assessment," is required to determine details on those hazardous qualities, and the specific ways people or the environment can be exposed.
Understanding the CEPA 1999 risk assessment process: Science is the key
A risk assessment is a scientific evaluation of a chemical substance. This evaluation determines the potential harm or danger a chemical substance can cause to human health and/or the environment, and the ways in which humans or the environment can be exposed to the substance. This allows the government to identify whether or not a control is needed, and if so, what type of control is best suited for avoiding, reducing or preventing the potential harm.
To conduct risk assessment, scientists conduct research and look at the existing studies from around the world, and if they are missing something important, they will use computer models or compare the chemical substance to others with similar characteristics. Specific information on the hazardous properties and the exposure possibilities for people and the environment helps the Government of Canada to find the right tools for controlling a chemical substance.
Each chemical substance is unique and some are more complex than others. The unique characteristics of chemical substances need to be considered when making decisions about the need for control or elimination. For example, it might be very easy to assess a chemical substance that has a single use. It gets more complicated, though, for chemical substances that have many different uses, enter the environment in many different ways, and may affect humans or non-human organisms differently depending on how they are encountered in the environment.
The number of chemical substances identified by categorization as needing further attention makes it impossible to evaluate all of them at once. Substances have to be prioritized so that those of greatest potential concern are addressed first.
A systematic approach to assessing chemical substances under CEPA 1999
Under CEPA 1999, Government of Canada scientists assess chemical substances in a number of ways:
Screening Assessments: A screening assessment looks at the hazardous properties of the chemical substance and the ways people and the environment are exposed to the hazard. Screening assessments can vary in complexity.
CEPA 1999 requires this type of assessment for all chemical substances on the Domestic Substances List (DSL) identified through categorization as requiring further attention. There can be three results at this stage: no further action is required, the chemical substance is determined to be toxic and measures may be needed for control, or it is placed on the Priority Substances List (PSL) and subjected to an in-depth assessment.
Priority Substances: Chemical substances on the Priority Substances List (PSL) are evaluated in depth. This evaluation can take up to five years and is considered a high priority for government scientists. PSL placement can happen after a screening assessment, a review of another government's assessment decision or at the request of any person (under certain conditions) or under other circumstances.
Reviews of decisions of other jurisdictions: The Government of Canada works with other governments in Canada and around the world to share information on chemical substances. When another government conducts a risk assessment, information is shared and Canadian government scientists review it to determine how to translate it into the Canadian context.
Making information available
The Government of Canada works with stakeholders such as the public, industry and health and environmental organizations to ensure that any decisions made on chemical substances are understood, and that the process used is transparent.
The Government of Canada and its partners:
- Share data, information and expertise
- Raise important new issues
- Develop new approaches to risk assessment
- Promote effective communication
Both draft and final risk assessments published under CEPA 1999 are made available in the Canada Gazette for a 60-day period to allow for comments from the public and concerned groups on the scientific findings.
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