What is a “toxic” or “hazardous” chemical?
In general, hazardous substances are ones that pose a significant threat to the environment, natural species, and human health. A more formal definition is found in the Canadian Environmental Protection Act (CEPA Section 64) which defines a substance as being “toxic” if it is entering, or may enter the environment in a quantity or concentration or under conditions that: • have or may have an immediate or long-term harmful effect on the environment or its biological diversity; • constitute or may constitute a danger to the environment on which life depends; or • constitute or may constitute a danger in Canada to human life or health. Two other terms of importance in determining the degree of hazard associated with a substance are: persistence: the length of time it takes a chemical to break down; and bioaccumulation: the ability of a substance to collect in the tissues of living organisms and to be passed up the food change. If a substance can be shown to be toxic, persistent, and it is
