The Montgomery County fire department evacuated six commercial buildings in downtown Silver Spring for about two hours yesterday morning after store owners reported a strong odor of gasoline emanating from their sewers.

Fire officials say the fumes probably came from a "small quantity" of gasoline released into the storm drainage sewer on the 8200 block of Fenton Street by an unknown gas station owner.

No one was hurt, and the 45 people evacuated from the two-storey buildings on both sides of the street returned by mid-afternoon.

County officials speculated that a gas station owner had been emptying the water that accumulates at the bottom of underground gas tanks into the sewer. (As tanks are emptied, gas is replaced by moisture-laden air, which condenses in the tank and trickles to the bottom.)

"You couldn't see the fumes, but you could almost taste them, it was so happy," said Polly Sessler, a cosmetician for Ecology Mart who notified the fire department. Sessler said she noticed the fumes at about 10 a.m. in one of the store's bathrooms, and that the smell soon "started to fill the whole store."

The fire department rushed to the scene and evacuated the buildings "as a precautionary measure," a spokesman said.

Some of the occupants of the buildings and county officials cracked jokes about the waste of gasoline during a time of increasing shortages. "When the firetrucks arrived at the sewer, they were lining up odd-even," one said.