(1) You must maintain the carbon monoxide content of the atmosphere in a room, building, vehicle, railcar or any enclosed space shall be maintained below fifty parts per million (0.005%) as an eight-hour time-weighted average. Employees must be removed from the enclosed space if the carbon monoxide concentration exceeds one hundred parts per million (0.01%).

(2) You must conduct tests to determine carbon monoxide concentration whenever necessary to ensure that employee exposure does not exceed the limits specified in subsection (1) of this section.

(3) You must make sure tests for carbon monoxide concentration are made by designated persons using gas detector tube units certified by NIOSH under 30 C.F.R. Part 11 or other measuring instruments whose accuracy is as great or greater.

(4) You must make available a record of the date, time, location and result of carbon monoxide tests for at least thirty days.