Factories and Industrial Undertakings Ordinance

(1)
In a proceeding for an offence under a provision in this Ordinance consisting
                of a failure to comply with a duty or requirement to do something so far as is
                necessary, where practicable, so far as is reasonably practicable, or so far as
                practicable or to take all reasonable steps, all practicable steps, adequate steps
                or all reasonably practicable steps to do something, the onus is on the accused to
                prove that it was not necessary, not practicable or not reasonably practicable to do
                more than was in fact done to satisfy the duty or requirement, or that he has taken
                all reasonable steps, or practicable steps or done the appropriate thing to satisfy
                the duty or requirement.
(2)
In a proceeding for an offence under a provision in this Ordinance consisting
                of an exemption from compliance with a duty or requirement to do something where it
                is impracticable, not reasonably practicable or rendered impracticable to comply
                with that duty or requirement, the onus is on the accused to prove that it was
                impracticable or not reasonably practicable to do more than was in fact done to
                comply with the duty or requirement.
(3)
Subsections (1) and (2) do not apply where the offence is committed on or
                before the commencement* of this section.