Oil and Gas Occupational Safety and Health Regulations

11.24 (1) Subject to subsections (2) and (3), the concentration of an airborne chemical agent or combination of chemical agents in a work place shall be less than 50 per cent of the lower explosive limit of the chemical agent or combination of chemical agents.

(2) Where a source of ignition may ignite the concentration of an airborne chemical agent or combination of chemical agents in a work place, that concentration shall not exceed 10 per cent of the lower explosive limit of the chemical agent or combination of chemical agents.

(3) Subsection (1) does not apply if

• (a) the work place is a Class I Division 1 or a Class I Division 2 area, as defined in section 18 of the Canadian Electrical Code;

• (b) the work place is equipped with an alarm system that will automatically be activated when the concentration referred to in subsection (1) exceeds 60 per cent of the lower explosive limit of the chemical agent or combination of chemical agents; and

• (c) no employee is exposed to a level in excess of 75 per cent of the lower explosive limit of the chemical agent or combination of chemical agents.