(a) for the time during which the person with the greatest degree of control is in compliance with the provision;

(b) where simultaneous compliance by more than one person would result in unnecessary duplication of effort and expense; and

(c) where the health and safety of persons at the workplace is not put at risk by compliance by only one person.

(5) Where the person with the greatest degree of control fails to comply with a provision described in subsection (2) but one of the other persons on whom the duty or requirement is imposed complies with the provision, the other persons, if any, to whom the provision applies are relieved of the obligation to comply with the provision in the circumstances set out in clauses 4(a) to (c) with the necessary modifications. 1996, c. 7, s. 23." - Occupational Health and Safety Act