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Bellevue Fire and Hazmat crews worked to mitigate a large fuel spill near Newcastle Monday night.

An unknown amount diesel fuel spilled into a stormwater drain that leads to Lake Washington. Bellevue Fire Batallion Chief Dave Beste said crews are still determining how many gallons spilled, and they've heard estimates anywhere between 30 gallons and 200 gallons.

"Any amount that gets into the lake is detrimental to the lake, so we take that seriously," Beste said.

The spill happened about 8 p.m. at the gas station on Southeast 64th and Lake Washington Boulevard, according to Bellevue Fire. A diesel delivery company was filling the underground tanks when the tanks overflowed, Beste said.

Mercer Island Marine Unit worked with Bellevue Fire to place booms around the sewer outflow to help contain the diesel. The booms, which are white round tubes filled with material that will absorb petroleum products, will help keep the fuel in one place so crews can clean it up later, Beste said.

Beste said he was not worried about any explosions, as diesel has a low explosive limit.

The Department of Ecology is working on a cleanup response with the diesel delivery company.