As a reminder, the following information was disseminated to the Industry in 1974:

Internal combustion engine driven equipment shall be operated inside of buildings or enclosed structures only when such operation does not result in harmful exposure to concentrations of dangerous gas or fumes in excess of threshold limit values. If concentrations exceed the limit values, venting or other engineering controls are to be used to ensure that workers are not exposed to concentrations exceeding the applicable exposure limits. Applicable exposure limits for British Columbia can be found in Part 5, Table 5-4 of the British Columbia Occupational Health and Safety Regulation.

Gas Operated Equipment Motion Picture Safety Bulletin PDF