Toxic substances list: sulphur hexafluoride
Sulphur hexafluoride (SF6) is a synthetic (i.e., human-made) gas that is colourless, odorless, non-toxic (except when exposed to extreme temperatures), and non-flammable. It is heavier than air and hence stays close to the ground upon release which can cause death by suffocation if large quantities are involved. SF6 is primarily used in the electricity industry as insulating gas for high voltage equipment. It is also used as cover gas in the magnesium industry to prevent oxidation (combustion) of molten magnesium. In lesser amounts, SF6 is used in the electronic industry in manufacturing of semiconductors, and also as tracer gas for gas dispersion studies in the industrial and laboratory settings. Sulphur hexafluoride acts as a greenhouse gas due to its very high heat trapping capacity.
Sulphur hexafluoride was added to Schedule 1 of CEPA in November 2005. Under subsection 90(1) of CEPA, a substance can be added to Schedule 1 of CEPA by the Governor in Council on the recommendation of the ministers of the environment and health if it is determined that a substance 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.
Based on an analysis of the existing science, most notably documented in the Third Assessment Report (TAR) of the Intergovernmental Panel on Climate Change (IPCC) and in subsequent reports including the Fifth Assessment Report (2014), there is sufficient evidence to conclude that the principal greenhouse gases namely carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulphur hexafluoride (SF6) constitute or may constitute a danger to the environment on which life depends. The addition of sulfur hexafluoride to schedule 1 of CEPA gives the Government the power to put in place a variety of preventative or control actions to control SF6 under that same Act. The reporting on releases of SF6 to the atmosphere is regulated under section 46 of CEPA and is required from large industrial and commercial facilities that meet a certain threshold for their combined emissions in CO2 equivalent of the six principal greenhouse gases.
CAS (Chemical Abstract Service) registry number: 2551-62-4
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