BENNINGTON — Firefighters and cleanup crews spent more than six hours Saturday containing 150 gallons of heating oil, a third of which had spilled into the Contoocook River.

Bennington Deputy Fire Chief Matthew Hall said someone alerted the department to an odor of fuel near School Street around 4 p.m., and firefighters discovered red fuel leaking into the river. They used spill booms to contain the polluted water to the culvert and followed the drain systems back to a house nearby, Hall said. The homeowner allowed the firefighters to inspect the basement, where a pump was removing residual water from the cellar and pushing it into the culvert system. But it was also pumping out heating oil, Hall explained, that was leaking from the tank “for God knows how long.”

Crews jumped to action, he said, shutting off the pump and placing more spill booms in the river to further contain the oil. The department called “basically everybody and their brother,” including the state environmental services and Clean Harbors, based in Bow.

Over six or seven hours, Hall guessed, the cleanup crews pumped about 150 gallons of oil, maybe 50 of which had spilled into the river. He said the fire department had managed to contain most of it with the spill booms.

Clean Harbors returned Sunday to continue removing oil from the house, and Hall said the organization would likely have more work to do later this week, including soil and water testing.

The Contoocook River ranges 71 miles, beginning from Pool Pond and Contoocook Lake on the Jaffrey-Rindge border. Only a few rivers in the state flow predominantly northward; the Contoocook is one.

Sierra Hubbard can be reached

at 355-8546 or at shubbard@keenesentinel.com.