Muni resumes service after small fire in downtown SF

Smoke in a Muni tunnel in downtown San Francisco near the Civic Center station prompted a fire investigation and temporary delays on the transit system Monday morning, officials said.

Minutes later, officials said they had extinguished a small debris fire in a fan room.

Jonathan Baxter, a fire agency spokesman, said the smoldering trash could have been caused by a number of factors, such as a discarded cigarette or sparks from the rail.