8.3.2. The test samples of the fresh air supply for concentration of carbon monoxide, nitrogen dioxide or other noxious gases in an underground work site shall be performed as often as necessary, but at least 2 times each day, and one of these, one hour after the beginning of operations. All test results shall be compiled and made available for the inspector’s examination.
R.R.Q., 1981, c. S-2.1, r. 6, s. 8.3.2.