Approximately 4,200 gals. of crude oil spilled Monday from an abandoned flow line off the coast of Louisiana, the Coast Guard said.

Oil leaked from a Hilcorp Energy-owned pipeline into Lake Grande Ecaille off of Plaquemines Parish, La. Hilcorp told Reuters on Tuesday that the cause of the leak was unknown, and estimated that 30 to 100 barrels of oil were released.

The company has contracted oil spill responders Environmental Safety and Health to spearhead cleanup operations. The response team has deployed approximately 2,400 feet of hard containment boom to prevent further impact to the area and are using skimmers and airboats to recover the product as well. Aircrews from Coast Guard Air Station New Orleans and Hilcorp Energy will continue to conduct over-flights to monitor oil recovery operations.

The source of the discharge has been secured, the Coast Guard said, and the agency is investigating the cause of the incident. The National Oceanic and Atmospheric Administration, Louisiana Oil Spill Coordinators Office, and Louisiana Department of Wildlife and Fisheries are also involved in response efforts.

Response crews place containment boom to prevent further impact to the area affected by a 4,200-gallon crude oil discharge near Lake Grande Ecaille, July 26, 2016. USCG photo.

Response crews place containment boom to prevent further impact to the area affected by a 4,200-gallon crude oil discharge near Lake Grande Ecaille, July 26, 2016. USCG photo.