Mitotane added to CEPA Schedule 1

Summary#

The federal government has added the chemical commonly called mitotane (full name: benzene, 1-chloro-2-[2,2-dichloro-1-(4-chlorophenyl)ethyl]-, CAS RN 53-19-0, formula C14H10Cl4) to Schedule 1 (the List of Toxic Substances) under the Canadian Environmental Protection Act, 1999. The Order was registered on October 6, 2020 and published in the Canada Gazette on October 28, 2020. This lets the government consider rules to limit environmental releases in the future, but it does not stop mitotane being used as an essential cancer drug in Canada.

What it does#

• Adds mitotane to Schedule 1 (the List of Toxic Substances) under the Order Adding a Toxic Substance to Schedule 1 to the Canadian Environmental Protection Act, 1999.
• Declares mitotane meets the environmental “toxic” test in the Act because it is persistent, can build up in living things, and can harm aquatic life at low concentrations.
• Triggers the possibility of future risk-management actions under the Act, including the option of “virtual elimination” (a formal aim to reduce releases to very low measurable levels).
• States that current medical use as a prescription cancer drug will not be limited by this Order. Direct patient use remains managed under the Food and Drug Regulations.

Who's affected#

• Patients and clinicians who rely on mitotane for treating cancers of the adrenal gland. Use in Canada is small but essential. Reported amounts of pharmaceutical use/import in past years include about 93 kg, 100 kg, and 60 kg in specific years, and typical annual import ranges were reported around 100 kg to 1 000 kg.
• Pharmaceutical suppliers or importers who handle mitotane.
• Municipal wastewater systems near where mitotane is used, because some of the drug can be excreted and enter wastewater.
• Aquatic environments and wildlife, since the substance is persistent, bioaccumulative, and toxic to fish and other aquatic organisms.
• Other Canadian government bodies involved in chemical risk management (for example, Health Canada and Environment departments), which may develop any future controls.

Why it matters#

• Adding mitotane to Schedule 1 gives the government a formal legal basis to design and propose rules to reduce environmental releases if needed. It does not automatically impose new limits or costs.
• Scientists concluded mitotane can harm aquatic life at low levels and sticks around in the environment. That’s the main reason it was listed.
• At the same time, regulators recognize mitotane is an important, sometimes necessary, cancer drug. The Order keeps medical use unchanged for now and leaves patient care to drug safety rules under the Food and Drug Regulations.
• If future controls are proposed, affected parties (including the public and industry) would be consulted and the costs and benefits of any measures would be examined.