35. Canada

Canada is treated here in brief, because the same installations and vehicles are operated and maintained there, because the same European manufacturers supply the market, and because the Canadian rules answer the substitution question differently from the American ones. Occupational safety is a provincial matter apart from federally regulated undertakings.

Quebec sets the strictest values in North America. Schedule I to the Regulation respecting occupational health and safety gives, for water-insoluble inorganic chromium(VI) compounds expressed as Cr, a time-weighted average exposure value of 0.001 mg/m³, and for water-soluble inorganic chromium(VI) compounds 0.005 mg/m³. Both entries carry the designation C1, “carcinogenic effect detected in humans”, and the designation EM, which marks “A substance to which exposure must be reduced to a minimum in accordance with section 42”. Section 42 reads: “Carcinogenic and isocyanate substances: When a worker is exposed to a substance identified in Schedule I as having a known or suspected carcinogenic effect on humans or being diisocyanate or isocyanate oligomers, such exposure shall be reduced to a minimum, even when it remains within the standards in that Schedule.” Section 39 requires, as far as possible, the replacement of dangerous substances that are sources of dusts, fumes, mists, vapours or gases. [170]

Ontario does not list chromium in its own table. Section 4 paragraph 2 of Regulation 833 under the Occupational Health and Safety Act directs that where an agent is not in the Ontario Table but is in the table of the American Conference of Governmental Industrial Hygienists, exposure shall not exceed the values set out there. The consolidated table of the provincial ministry accordingly gives water-soluble chromium(VI) compounds as Cr at 0.05 mg/m³ and insoluble chromium(VI) compounds at 0.01 mg/m³, each as an eight-hour average, with the excursion limits of paragraph 3 applying because no short-term or ceiling value is set. Section 3 paragraph 2 of the same regulation lists the measures to be taken and names substitution first. [171]

British Columbia has the provision that the American standards lack. Section 5.57(1) of the Occupational Health and Safety Regulation provides that where a substance carrying the ACGIH A1 or A2 notation or the IARC 1, 2A or 2B notation is present in the workplace, “the employer must replace it, if practicable, with a material which reduces the risk to workers”, and where that is not practicable, subsection (2) requires an exposure control plan keeping exposure as low as reasonably achievable below the exposure limit. Both chromium(VI) entries in the WorkSafeBC table of exposure limits carry A1 and 1, so the provision applies to them; the limits are 0.01 mg/m³ for insoluble and 0.025 mg/m³ with a ceiling of 0.1 mg/m³ for water-soluble compounds, with dermal and respiratory sensitizer notations. Section 5.55(1) sets out the general order of measures, with substitution first. [172]

Safety data sheets follow the Hazardous Products Regulations made under the Hazardous Products Act, which implement the Workplace Hazardous Materials Information System. Item 10 of Schedule 1 to those regulations requires, under the heading “Stability and reactivity”, the reactivity, the chemical stability, the “possibility of hazardous reactions”, the conditions to avoid, the incompatible materials, and the “hazardous decomposition products”. What the Canadian-format sheets of the manufacturers concerned enter under that item is set out in Section 36. [173]

For federally regulated undertakings the Canada Occupational Health and Safety Regulations add a general provision under the heading “Substitution of Substances”, section 10.16: “No person shall use a hazardous substance in a work place if a non-hazardous substance or one that is less hazardous can be used instead.” [174]

The result for North America is uneven. The United States have the broadest standard and no substitution duty. Quebec has the lowest limit value and a duty to minimise. British Columbia has a substitution duty keyed to carcinogenicity. Ontario reaches its values by reference to a private body of recommendations. None of these jurisdictions names the formation of chromates on insulated chromium-alloyed hot components.