S-2.1, r. 4 - Safety Code for the construction industry

Full text
8.3.4. The employer shall ensure that the fresh air supply for the ventilation system is without impurities, and for this purpose:
(a)  the ventilation ducts shall be placed so as to prevent the return of foul air into the air supply system through the shaft or tunnel entrance; and
(b)  vehicles not directly involved in the underground work site shall be kept at a distance of at least 15 m from the access or opening connected to the underground work site.
R.R.Q., 1981, c. S-2.1, r. 6, s. 8.3.4.