A contract worker was killed and two others injured in an accident on a Chevron gas pipeline off the Louisiana coast Saturday while performing routine maintenance.

The two workers were taken by helicopter to meet an ambulance on-shore, but both declined to go to the hospital after being evaluated by medics.

The cause of the offshore accident was under investigation, a Chevron Pipe Line Co. spokesman said. According to George Langley, a spokesman for the Louisiana Department of Environmental Quality, the gas-handling line suffered a valve failure about 11:10 a.m. Saturday. The gas flow was halted as the investigation was conducted and repairs completed.

According to the U.S. Coast Guard, the incident occurred approximately 6 miles south of Timbalier Bay off the southeast Louisiana coast.