NEW ORLEANS — The Coast Guard said about 88,200 gallons of oil have leaked from a Shell flow line into the Gulf of Mexico, about 90 miles off the coast of Louisiana.

Chief Petty Officer Bobby Nash said the leak, which was reported on Thursday, had been secured and cleanup crews would be dispatched. Officials are investigating the cause.

Officials said the oil came from a line connecting four wells in the Green Canyon area of the gulf to Shell’s Brutus platform and has left a mileslong sheen.

The Bureau of Safety and Environmental Enforcement said there were no reports of injuries.

Officials said that Shell Offshore reported the spill and that it had shut the wells flowing into the line.