BRUNSWICK — Cleanup crews managed to recover about half of the 63,000 gallons of jet fuel that leaked from pipelines at Brunswick Naval Air Station, officials said Wednesday.

Lt. Kurt Wallisch, base spokesman, said crews recovered 40,000 gallons of greasy water — which amounts to 30,000 gallons of fuel — from a marshy area near the Androscoggin River.

Most of the fuel, which floats in water, formed puddles that made the cleanup easier for workers using pumps and skimmers.

“All the moisture in the ground is keeping the product from sinking into the soil,” said Lt. Scott Higgins, director of Brunswick Fire Department’s hazardous waste cleanup team.

Higgins said between evaporation and cleanup that he expects only 10 percent of the spill to remain in the environment.

The fuel spill was caused when two valves on fuel pipelines were opened over the weekend. The fuel spilled into a storm drain and directly into the tributary. The problem wasn’t noticed until Monday morning.