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Canada - Final Regulatory Action
N-Nitrosodimethylamine CAS number:
Date circular:

Chemical name: Methanamine, N-methyl-N-nitroso-

Final regulatory action has been taken for the category: Industrial

Final regulatory action: The chemical is Severely Restricted

Use or uses prohibited by the final regulatory action:

The Regulations prohibit the manufacture, use, sale, offer for sale or import of NDMA, or a mixture or product containing NDMA, unless the substance is incidentally present.

Use or uses that remain allowed:

The Regulations do not apply to NDMA that is:
contained in a hazardous waste, hazardous recyclable material or non-hazardous waste;
contained in a control product (e.g., pesticide);
present as a contaminant in a chemical feedstock used in a process from which there are no releases of the substance and provided that the substance is destroyed or completely converted in that process to a substance that is not listed in Schedule 1 or 2 of the Regulations; or
used in a laboratory for analysis; in scientific research; or as a laboratory analytical standard.
The Regulations also establish a permit system that provides a mechanism for temporarily exempting certain applications of a substance listed in the Regulations. A permit may be granted only if the Minister of the Environment is satisfied that there is no technically or economically feasible alternative or substitute available for the substance. In addition, the Minister must be satisfied that measures have been taken to minimize or eliminate any harmful effects of the substance on the environment and human health. Finally, the applicant must provide an implementation plan that identifies specific timelines for eliminating the substance. Each permit lasts for 12 months, and can be renewed only twice.

The final regulatory action was based on a risk or hazard evaluation: Yes

Summary of the final regulatory action:

The Prohibition of Certain Toxic Substances Regulations, 2005 prohibit the manufacture, use, sale, offer for sale and import of toxic substances listed in Schedules 1 and 2 to the Regulations. NDMA is found on Schedule 1, which lists substances subject to total prohibition, with the exception of incidental presence.

The reasons for the final regulatory action were relevant to: Human health

Summary of known hazards and risks to human health:

The Canadian Environmental Protection Act, 1999 (CEPA 1999) requires the Ministers of the Environment and of Health to prepare and publish a Priority Substances List that identifies substances, including chemicals, groups of chemicals, effluents and wastes that may be harmful to the environment or constitute a danger to human health. The Act also requires both Ministers to assess these substances and determine whether they are "toxic" or capable of becoming "toxic" as defined in the Act, which states:
"A substance is toxic if it is entering or may enter the environment in a quantity or concentration or under conditions that
(a) have or may have an immediate or long-term harmful effect on the environment or its biological diversity;
(b) constitute or may constitute a danger to the environment on which life depends; or
(c) constitute or may constitute a danger in Canada to human life or health."
A description of the approach to assessment of the human health effects of Priority Substances is available in the published document "Canadian Environmental Protection Act - Human Health Risk Assessment for Priority Substances" ( It should be noted that the approach outlined in this document has evolved to incorporate recent developments in risk assessment methodology, which will be addressed in future releases.
Data relevant to the assessment of the potential risks of NDMA to human health were identified through evaluation of existing review documents of the U.S. Agency for Toxic Substances and Disease Registry, the International Agency for Research on Cancer and the Ontario Ministry of the Environment, as well as reviews prepared under contract by BIBRA Toxicology International. To identify additional relevant toxicological data, literature searches on NDMA were conducted using the strategy of searching by its name or CAS registry number in a variety of databases (see Assessment Report for a complete list). The EMBASE database, for 1981-1999, was searched using the name, registry number and major synonyms, combined with a link to toxicological information. In addition to the above sources of information, numerous provincial and federal government officials and representatives of various industrial sectors were contacted between February and August of 1996 for data relevant to exposure and/or effects.
A survey of Canadian industry was carried out under authority of Section 16 of the original CEPA. Companies were required to provide information on uses, releases, environmental concentrations, effects or other data on NDMA available to them if they met the trigger quantity of 10 g NDMA per year. Data obtained after August 31, 1998 were not considered in this assessment unless they were critical data received during the 60-day public review of the report (February 19 to April 19, 2000).
NDMA was released to the Canadian environment as a by-product and contaminant from various industries and from municipal wastewater treatment plants. Major releases of NDMA have been from the manufacture of pesticides, rubber tires, alkylamines and dyes. NDMA was also detected in drinking water and in automobile exhaust. Sources of release of NDMA may have occurred across Canada, but releases were quantified only in Ontario. NDMA may also form under natural conditions in air, water and soil as a result of chemical, photochemical and biological processes.
NDMA was not detected in ambient air, except in the vicinity of industrial sites, in small surveys of several cities in southern Ontario. Low concentrations of NDMA were measured in drinking water in Ontario, where sources included the contamination of groundwater with industrial effluents and the formation of NDMA in water treatment plants. The presence of NDMA was demonstrated in some foods in Canada, most frequently in beer, cured meat and fish products, and some cheeses, although levels of NDMA had decreased in these products owing to changes in food processing. Some of these changes were mandated under the Canadian Food and Drugs Act and Regulations.
Based on available data, it was concluded that NDMA was entering the environment in a quantity or concentration or under conditions that constituted or may have constituted a danger in Canada to human life or health. Therefore, NDMA was considered to be "toxic" as defined in CEPA 1999. This approach is consistent with the objective that exposure to substances where cancer is likely induced through direct interaction with genetic material be reduced wherever possible and obviates the need to establish an arbitrary "de minimis" level of risk for the determination of "toxic" under CEPA 1999.

Expected effect of the final regulatory action in relation to human health:

NDMA is not currently used, sold, produced, imported or exported in Canada. The Regulations ensure that NDMA is not introduced into the Canadian market, which could represent an increase in risk to Canadians' health.

Date of entry into force of the final regulatory action: 15/05/2005