Toxic substances list: Chlorinated Alkanes

The term paraffins used to identify these substances was changed to alkanes to harmonize with more current nomenclature that is recognized by other jurisdictions and international bodies.

Chlorinated alkanes are chlorinated hydrocarbons (n-alkanes) that can have carbon chain lengths ranging from 10 to 38 carbon atoms. They are generally grouped by chain length: short-chain chlorinated alkanes (SCCAs) (containing 10-13 carbon atoms), medium-chain chlorinated alkanes (MCCAs) (containing 14-17 carbon atoms) and long-chain chlorinated alkanes (LCCAs) (with 18 or more carbon atoms). SCCAs have been found in the Arctic food web. The higher volatility of certain short-chain compounds suggests that their presence resulted from long-range atmospheric transportation.

Chlorinated alkanes are no longer manufactured in Canada, but are still imported into Canada and used in the manufacturing of rubber and the formulation of metalworking fluids (i.e. cutting fluids, high pressure lubricating oils). Other uses include as a plasticizer or flame retardant in various plastics or formulated chemical products (e.g. adhesives, paints, sealants).

Chlorinated alkanes were included on the first Priority Substances List (PSL) program under the 1988 Canadian Environmental Protection Act for assessment of potential risks to the environment and human health. In 1993, Environment and Climate Change Canada and Health Canada published an assessment report that concluded SCCAs constitute or may constitute a danger to human health or life as set out in the Act. On August 30, 2008, a notice summarizing the scientific considerations of a final follow-up assessment report was published by Environment and Climate Change Canada and Health Canada in the Canada Gazette, Part I for chlorinated alkanes.

The final follow-up assessment report concluded that chlorinated alkanes containing up to 20 carbon atoms are 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 and meet the definition of “toxic” under paragraph 64(a) of the Canadian Environmental Protection Act (1999) (CEPA). In addition, based on that report and a 2012 Update on the Human Health Assessment for LCCAs, it was concluded that SCCAs and MCCAs are entering or may enter the environment in a quantity or concentration or under conditions that constitute or may constitute a danger in Canada to human life or health and therefore meet the criteria under paragraph 64(c) of CEPA. Chlorinated alkanes that have the molecular formula C_nH_xCl_(2n+2–x) in which 10 ≤ n ≤ 20 have been added to Schedule 1 to CEPA.

Furthermore, these chlorinated alkanes containing up to 20 carbon atoms meet the criteria for persistence and bioaccumulation potential as set out in the Persistence and Bioaccumulation Regulations and were recommended for virtual elimination. Under Bill S-5, Strengthening Environmental Protection for a Healthier Canada Act, the virtual elimination provisions were repealed and replaced with a new regime that remains risk-based but provides that toxic substances of highest risk should be managed by giving priority to prohibition. SCCAs were added to the Prohibition of Certain Toxic Substances Regulations, 2012 in January 2013. These Regulations prohibit the manufacture, use, sale or import of SCCAs, and products containing them, in Canada, with a limited number of exemptions.

In February 2025, Environment and Climate Change Canada and Health Canada published a Consultation Document on the Risk Management on Short-chain, Medium-chain and Long-chain Chlorinated Alkanes for a 60-day public comment period. The objective of this consultation document is to:

inform stakeholders and solicit comments on the proposed regulatory approach to prohibit the manufacture, import, use and sale of MCCAs and LCCAs up to 20 carbon atoms, and products containing them, through their addition to the Prohibition of Certain Toxic Substances Regulations, 2012
solicit information regarding concentration thresholds for SCCAs and MCCAs; and
outline and solicit comments on the proposed regulatory approach to control the exports of SCCAs, MCCAs and LCCAs up to 20 carbon atoms through their addition to the Export Control List (ECL) in Schedule 3 to CEPA.

Comments received will be considered in the development of proposed regulatory instruments.

For more information on this substance, please visit the Chemical Substances website.

Risk assessment

These substances have been added to Schedule 1 of CEPA. They are 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 and SCCAs and MCCAs constitute or may constitute a danger in Canada to human life or health.
Update on the Human Health Assessment of Long-Chain Chlorinated Alkanes (May 2012)
Final Follow-Up Assessment Report on Chlorinated Paraffins (August 2008)
Priority Substances List Assessment Report (1993)