Singapore legislation
Regulation 40
of Workplace Safety and Health (General Provisions) Regulations
Regulation 40
Permissible exposure levels of toxic substances
Subregulation 1
It shall be the duty of the occupier of a workplace to take all reasonably practicable measures to ensure that no person at work in the workplace is exposed to the toxic substances specified in the First Schedule in excess of the permissible exposure levels specified in that Schedule.
Subregulation 2
Where the PEL (Short Term) of a toxic substance is not specified in the First Schedule, the PEL (Short Term) of the substance shall be deemed to be exceeded if the time weighted average concentration of the substance measured over a 15-minute period during any working day exceeds 5 times the PEL (Long Term) of that substance as specified in that Schedule.
Subregulation 3
Where there is exposure to more than one toxic substance at the same time and the substances have similar harmful effects, the permissible exposure level shall be deemed to have been exceeded if the sum of the ratios between the time weighted average concentration and the permissible exposure level of each substance exceeds one.