They may use underwater video, sonar and other recording equipment for scientific or exploratory purposes. They may also participate in search and rescue, recovery and clean-up operations. With training and experience they may supervise and train other divers, especially hobby divers. Construction divers perform construction duties, such as welding and installing pilings or footings for piers. They also maintain these and other structures.
Some divers inspect ships, plant outflows, pipelines, sluice gates, and so on.
In salvage operations, divers use winches, derricks or cranes to raise sunken objects, or they may use explosives to remove obstructions and break up or refloat submerged objects. All divers must also check and maintain their own diving equipment, such as helmets, masks, air tanks, harnesses and gauges. Some may also be involved in atmospheric diving, using submarine-like vehicles to do their work. In order to become a commercial diver employed with a construction company, graduation from secondary school and a recognized commercial diving school program are usually required. Divers must meet the Commercial Diving Competency Standards of the Canadian Standards Association.