SAN FRANCISCO (KTVU and wires) -- Caltrans engineers determined that the two fires this week in an expansion joint on the new eastern span of the Bay Bridge were caused by road flares, a spokeswoman said Wednesday.
The fires, one Wednesday afternoon and one Monday night, both started in an expansion joint in the eastbound lanes of Interstate Highway 80 just east of Treasure Island, according to the California Highway Patrol.
A fire coming from beneath the bridge and up through the expansion joint into the roadway was first reported on Monday around 10 p.m. near the Treasure Island exit. The blaze, quickly extinguished, blocked two lanes of traffic for around an hour.
A second fire was spotted just after noon Wednesday, with lanes reopening around 1:50 p.m.
Caltrans spokeswoman Leah Robinson-Leach said the fires damaged the rubber seal on the joint, which protects it from debris and saltwater, and repairs will be needed. However, the damage has not created any safety hazards for drivers, she said.
The cause of the fires being attributed to road flares was announced shortly after 5:30 p.m. Officials used surveillance video to determine flares were the cause. A Caltrans official said the fire on Monday was caused by a flare that had been left behind by crews working on the span.
Caltrans has not yet determined when repairs on the seal and joint will take place, she said.