Chemical name: Methane, chloromethoxy-

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 CMME, with the exceptions listed below.

Use or uses that remain allowed:

The Regulations do not apply in the case of incidental presence or for use in a laboratory for scientific research purposes or as a laboratory analytical standard.

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. CMME is found in Schedule 1, which lists prohibited toxic 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 assessment of substances to determine if they are toxic under the Canadian Environmental Protection Act (CEPA) is a shared responsibility of Environment Canada and Health Canada. Environment Canada assesses the environmental risks, and Health Canada assesses the human health risks. An assessment was conducted to determine if a substance is likely to harm the environment or the health of humans, taking into account the likelihood and magnitude of releases at levels occurring in the Canadian environment. Thus toxic in the context of CEPA is a function of both the inherent properties of a substance and the amounts, concentrations, or nature of entry of the substance in the Canadian environment.

The assessment process thus provides a framework for making science-based decisions on the effective management of toxic substances that are of concern. The determination of whether or not a substance is toxic must be based on sound, scientifically reliable data. Under the original CEPA, a substance is toxic if it is entering or may enter the environment in a quantity or concentration or under conditions that

1. have or may have an immediate or long-term harmful effect on the environment or its biological diversity;
2. constitute or may constitute a danger to the environment on which life depends; or
3. constitute or may constitute a danger in Canada to human life or health.

CMME has been demonstrated to cause cancer in experimental animals and in humans. It was therefore considered to be a non-threshold toxicant (substance for which it is believed to be some chance of adverse health effects at any level of exposure). Owing to the lack of available information on concentrations in several environmental media to which humans are exposed, it was not possible to quantitatively estimate the total daily intake of CMME by the general population in Canada. It was also considered not appropriate to estimate intake on the basis of fugacity modeling, owing to the lack of commercial activity reported for these compounds. Consequently, estimates of total daily intake could not be compared to quantitative estimates of cancer potency to characterize risk and provide guidance in establishing priorities for further action under CEPA. For CMME, such values would be expected to be extremely low owing to the lack of exposure in the general environment.

In prospective (cohort) studies of 125 employees of a chemical plant in the United States, 737 exposed and 2120 unexposed workers at a chemical plant in Philadelphia and 2460 exposed and 3692 unexposed workers at seven industrial facilities, the standardized mortality ratios for lung cancer were 20, 2.8, and 3, respectively. In one of the studies, the standardized mortality ratios for deaths due to lung cancer peaked 15 to 19 years from the onset of exposure; similarly, another of the studies reported that the greatest increase in deaths due to cancer of the respiratory tract occurred approximately 10 to 20 years after first exposure.

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

CMME was prohibited under the original Prohibition Regulations. At that time it was not used, sold, produced, imported or exported in Canada. The amended Regulations continue to prohibit the manufacture, use, sale, or import of CMME towards the objective of virtual elimination.

Summary of known hazards and risks to the environment:

CMME is readily degraded by hydrolysis in aqueous media or by photo-oxidation in the atmosphere, and therefore is not likely to accumulate within living organisms. Because of its extremely short residence time, it is believed that levels in the environment were extremely low (if they existed at all), and there was no exposure that could potentially arise from the past use of this substance in Canada. Therefore, even though there was a complete absence of data concerning the environmental toxicity of these substances, there was no reason to suspect that adverse effects due to CMME could occur in organisms living in the Canadian environment.

The short persistence of CMME in the atmosphere and the extremely low levels of release preclude this substance from contributing to ozone layer depletion, global warming, or photochemical smog formation.

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