Commercial divers install, maintain, or repair underwater structures, such as offshore oil and gas rigs, bridges, and other underwater structures using scuba gear. Their duties and responsibilities may also include the inspection of these structures on a regular basis. Specific tasks may include cutting and welding using specialized underwater equipment and installing support structures, such as legs and rigging, for facilities on the open water. Some commercial divers also perform search and rescue or salvage missions after disasters. They may be asked to make deep water recoveries or repairs.