143.1(1)If a blast could cause the release of gases into areas where employees are working, the person who conducts an underground blasting operation shall, before blasting, cause all entrances to the area and all areas where the health or safety of employees may be endangered by the blasting to be guarded so as to prevent access to the areas during blasting.

143.1(2)An employer shall establish a code of practice for the blasting operation referred to in subsection (1), ensure that the code of practice is followed and make a copy of the code of practice available to an officer and the committee on request.