Commonwealth Consolidated Regulations Commonwealth Consolidated RegulationsIf a hazardous substance is contained in an enclosed system (including, for example, a pipe, a piping system, a process vessel or a reactor vessel), the operator that controls the enclosed system must ensure that:
(a) the existence of the hazardous substance is disclosed to all persons who could be exposed to the hazardous substance; and
(b) the hazardous substance is identified clearly to those persons.