312.74. Exceptional preventive measures: In addition to the general preventive measures referred to in sections 312.68 to 312.73, the exceptional preventive measures prescribed in sections 312.75 to 312.79 apply to any dive operation in a contaminated environment conducted in one of the following locations:(1) at the discharge point or in the vicinity of the discharge point of effluents from an industrial plant, a water treatment or wastewater purification station;
(2) in the vicinity of a chemical, biological or radioactive pollutant spill; or
(3) in a nuclear plant.
Likewise, the measures apply if sediments containing contaminants are moved with equipment resulting in their suspension at the underwater workstation.