Chlorinated Naphthalenes fact sheet

What are they?

• Chlorinated Naphthalenes (CNs) are a group of chemical substances that may be released as by-products of industrial processes. There are 75 possible CNs which are divided into eight groups based on the number of chlorine atoms in the molecule (referred to with prefixes mono- to octa-)

How are they used?

• CNs have not been in commercial use in Canada for more than two decades, but may be produced unintentionally as a by-product of various industrial processes involving chlorine.
• CNs were likely never manufactured in Canada but were imported from manufacturers in the U.S. decades ago.

Why is the Government of Canada assessing them?

• CNs were identified as a potential danger to the environment based on available information regarding possible persistence, accumulation in organisms and potential to cause harm to organisms.

How are they released into the environment?

• Because CNs are produced unintentionally as by-products of industrial processes, they may be released to the environment from a variety of sources. They can then stay in the environment for a long time.
• Industrial processes involving chlorine (especially in the presence of heat) that may produce CNs as a by-product include waste burning, cement and magnesium production, refining of metals, drinking water chlorination and pulp and paper production.
• CNs can also be released to the atmosphere from domestic wood-burning, or naturally during forest fires.
• CNs tend to be present in air and/or soil if released to air, and in water and sediment if released to water.
• CNs may enter the environment in a sufficient quantity or under conditions that would be harmful to the environment and its biological diversity.

What is the Government of Canada doing?

• The Government of Canada has conducted a science-based evaluation of CNs called a screening assessment.
• The Government of Canada has determined that CNs with two to eight chlorine atoms (di- through octa-) are entering or may enter the environment in a quantity or under conditions that may constitute a danger to the environment.

What can Canadians do?

• Because exposure to CNs is very low, Canadians do not need to take specific actions to reduce their exposure.