The Ontario Ministry of Labour (Canada) is seeking input on the proposed adoption of new or revised occupational exposure limits (OELs) or listings for 27 chemical substances. The proposed limits are based on recommendations by the American Conference of Governmental Industrial Hygienists, (ACGIH), an internationally recognized authority on occupational health. ACGIH recommendations regarding exposure limits are the basis of OELs in many North American and other jurisdictions. The proposal includes the adoption of a single more protective OEL for all types of crystalline silica. The proposed OEL for crystalline silica is 0.025 mg/m³.

In the European Union there is still no limit-value for cristalline silica, one of the most common carcinogens at the workplace. The Scientific Committee for Occupational Exposure Limits (SCOEL) has proposed since June 2002 a limit-value of 0.5 mg/m³.

• New list of proposed OELs in Ontario