A helicopter bound for U.S. offshore oil fields crashed in marshlands southwest of New Orleans, killing eight people and leaving a ninth with critical injuries, officials said, according to AP. The helicopter, operated by PHI Inc., crashed shortly after taking off Sunday afternoon from PHI's base in Amelia, Louisiana, company spokesman Richard Rovinelli said. The cause of the crash was not clear. Rovinelli did not know the type of helicopter or its exact destination. He said the helicopter was carrying two pilots and seven passengers when it went down in the marshy Bayou Penchant area about 100 miles (161 kilometers) from New Orleans. The victims have not been identified by name. Investigators from the National Transportation Safety Board were expected to arrive Monday, Rovinelli said. The Coast Guard assisted Terrebonne Parish sheriff's deputies in recovering the dead and rescuing the survivor, Petty Officer Jaclyn Young said. A spokesman for the sheriff's office could not be reached for comment. Young said the survivor was transported in critical condition to Ochsner Medical Facility in suburban New Orleans.