Rapid City fire crews Friday mopped up 75 to 100 gallons of gasoline spilling from tanks at an East North Street service station and pouring across parking lots at the station and a McDonald's restaurant before running into a storm drain.

The incident forced fire crews and Rapid City police to divert traffic and isolate the area for about two hours during the cleanup.

"It's been awhile, but we've had spills that big before," Fire Station One Battalion Chief Rob Powell said.

He said the spill happened about 2:30 p.m. when a gasoline tanker driver accidentally overfilled Big D's underground storage tank.

Firefighters spread absorbent kitty litter on the fuel and placed hazardous material booms into the storm drains to absorb gasoline that had run off. Officials said the spill was confined to a containment area before it could enter any water supply. State Department of Environment and Natural Resources officials were called in to check for any environmental damage, as is routine in such cases.

A city street sweeper collected the absorbent product, which was disposed of at the city landfill, Powell said.