Communicate with workers on the surface while underwater, using signal lines or telephones.

Take appropriate safety precautions, such as monitoring dive lengths and depths and registering with authorities before diving expeditions begin.

Check and maintain diving equipment, such as helmets, masks, air tanks, harnesses, or gauges.

Descend into water with the aid of diver helpers, using scuba gear or diving suits.

Obtain information about diving tasks and environmental conditions.

Inspect and test docks, ships, buoyage systems, plant intakes or outflows, or underwater pipelines, cables, or sewers, using closed circuit television, still photography, and testing equipment.