Canada – Newfoundland and Labrador Offshore Marine Installations and Structures Occupational Health and Safety Transitional Regulations

136 (1) Subject to subsections (2) and (3), the concentration of an airborne chemical agent or combination of chemical agents in a workplace must be less than 50% of the lower explosive limit of the chemical agent or combination of chemical agents.

(2) If a source of ignition may ignite the concentration of an airborne chemical agent or combination of chemical agents in a workplace, that concentration must not exceed 10% of the lower explosive limit of the chemical agent or combination of chemical agents.

(3) Subsection (1) does not apply if

• (a) the workplace is a hazardous location as defined in the Canadian Electrical Code, published by the CSA;

• (b) the workplace is equipped with an alarm system that will automatically be activated when the concentration referred to in subsection (1) exceeds 60% 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% of the lower explosive limit of the chemical agent or combination of chemical agents.