Fire raging out of control in an uncompleted subway tunnel beneath the Hollywood Freeway collapsed part of the tunnel today and forced closure of the freeway, snarling morning commuter traffic in much of downtown Los Angeles.
Six workers facing a wall of flame escaped harm when they dashed under the freeway to safety, but two of about 150 firefighters battling the blaze sustained minor injuries. What started the fire was not immediately determined.
Fire officials said wooden shoring and highly flammable plastic lining were burning the length of the 750-foot bore, threatening a more complete collapse of the tunnel that officials say could keep the freeway closed for weeks.
The fire--by far the worst accident to mar construction of Los Angeles' Metro Rail Red Line subway system--was expected to further delay completion of the project, which already is 18 months behind schedule.
It could add millions of dollars to the $1.4-billion cost for the first phase of the subway project, which already is running $135 million over budget. Officials say each day of delay costs $100,000 in interest and escalating costs alone, but Southern California Rapid Transit District spokesmen said the loss to the tunnel itself is covered by insurance.
Clouds of moderately toxic smoke from the burning plastic liner forced firefighters to don protective masks, further complicating a task already made arduous by temperatures in the mid-90s and high humidity.
Air superheated by the blaze created a "bazooka" effect, spurting flames that at times shot 100 feet into the air from both ends of the tunnel.
At dawn, about three hours after the fire broke out, smaller jets of flame began erupting through the ground above the tunnel and marched toward the freeway, marking the steady advance of the collapsing tunnel roof. By noon, about 150 feet of the tunnel had caved in, reaching to within 10 feet of the freeway.
The blaze struck a day before the scheduled opening of Metro Rail's intersecting Blue Line light-rail system between the downtown area and Long Beach. Officials said the opening should proceed as scheduled.
Two safety engineers on the subway project said the construction of the tunnel--one of a pair leading from the Union Station railway and subway terminal to a subway maintenance yard on the other side of the freeway--has been plagued with safety problems.
The engineers, who spoke on condition of anonymity, said there was a small fire recently in the other of the twin tunnels.
The twin tunnels--A-130 Left and A-130 Right--will not be used for passenger traffic on the 4.4-mile subway system between MacArthur Park and Union Station. Instead, they will carry empty trains between Union Station and a maintenance yard now under construction beside the Los Angeles River.
As they were dug, each tunnel was shored with wooden lagging beams--each about 6 inches thick, 12 inches wide and 4 feet long--held in place against the tunnel wall by a series of 17-foot steel rings that extend down the length of the tunnel like the ribs of a whale. Fiber packing was crammed between the beams to ensure a tight fit.
The shoring was then covered by a polyethylene membrane about an eighth of an inch thick to seal out flammable gases, such as methane, that abound underground in the Los Angeles area.
Tunnel A-130 Right is largely completed, its shoring and liner covered with a thick concrete lining. But in Tunnel A-130 Left, the one that was burning, the concrete had yet to be poured and the flammable packing and liners were still exposed. No underground passageways connect the tunnels, which are about 12 feet apart and top out about 15 feet below the pavement of the Hollywood Freeway.
Fire officials said the blaze apparently started about 1:50 a.m. in A-130 Left. No one was in that tunnel at the time, officials said, but half a dozen men were working in A-130 Right.
Andrea Greene, a spokeswoman for the SCRTD, which has overall authority over the project, said the workers heard the roar of the flames in the adjacent tunnel and ran to the west end of their tunnel to escape.
As they neared the west portal, she said, they saw a "bright light" from the flames billowing forth at that end. She said the men turned and ran back through their tunnel to safety at the east portal.
Firefighters responded quickly to the scene, but there was little question of their entering the burning tunnel to battle the flames.
"You can't put a man in there," one of the safety engineers said. "It would be like walking into a burning chimney."
Instead, firefighters adopted a "defensive position," aiming fans and fire hoses into each end of the tunnel to contain the fire and wait until it burned itself out.
By 5 a.m., the tunnel roof began to collapse. The surface of the ground sagged and broke through the failing roof, and flames began breaking through to the surface.