Poor Ventilation May Halt Tunnel Work for a Week : Metro Rail: Builders hope temporary fans will allow construction to resume Monday. Cal/OSHA officials express doubt.

Construction on the Metro Rail subway system under downtown Los Angeles cannot resume until Monday, and might be delayed for as long as a week, officials said Friday.

Work was halted Thursday when state safety engineers determined that a ventilation system was failing to clear the subway’s twin tunnels of noxious fumes generated by diesel equipment being used by construction crews.

A detailed plan to solve the problem was to be be submitted to Cal/OSHA this morning--a day later than originally scheduled.

Ed McSpedon, president of the Rail Construction Corp., which is supervising the project for the Los Angeles County Transportation Commission, said the plan includes the installation of six powerful fans--two at each end of the twin 4.4-mile-tunnel system and two in the middle--to pump in fresh air that would exhaust through vents along the route.

“The sense is that that ought to do it,” McSpedon said. “If Cal/OSHA is satisfied, we’ll go back to work on Monday, as usual. One way or another, we’re going to do it.”

McSpedon was referring to the resumption of full-scale construction work, involving 390 workers. He said that if the ventilation plan is approved this morning, work on a few small jobs might begin by this afternoon.

But a Cal/OSHA engineer, who spoke on condition of anonymity, said he thought it would take a lot longer--”maybe a week”--before ventilation is deemed adequate to allow work to resume.

“This is a major problem, something of a serious nature,” the engineer said. “You’re going to need a lot of ventilation in there to run those diesels. I doubt they will get our approval on Saturday morning.”

The engineer said he thought fans twice as powerful as those being proposed would be required to provide adequate ventilation. He said locating, installing and approving such equipment could take another week.

There’s no estimate yet of how much further the ventilation problem will postpone completion of the troubled, $3.9-billion project, which already is $135 million over budget and at least 18 months behind schedule. Before this latest setback, officials said they expected the trains to be running by September, 1993.

As for the added expense, “somebody’s going to have to pay for this down time,” McSpedon said. “We’re not sure yet who.”

The current shutdown is the latest in a series of problems for the project.

A tunnel fire last year did $2.2 million worth of damage and exposed numerous safety problems in the project. Other accidents have injured at least three, and a Times survey last year revealed a worker injury rate that far exceeded the national average. Leaks found last March in the plastic tunnel liner cost $2.5 million to repair.

McSpedon said that Cal/OSHA’s review of the new ventilation plan--originally scheduled for Friday morning--had to be a postponed a day because construction crews were unable to get the portable fans operating on time.

Both he and the Cal/OSHA safety engineer agreed that a longer-term solution would be to start up the much larger permanent ventilation system that will be in use once the trains are running.

Cal/OSHA said the builders apparently have delayed utilization of that system to avoid expending some of the warranty time from the manufacturers.

McSpedon and Cal/OSHA said that it would take at least two more weeks to get that system into operation.

An alternative short-term solution proposed by McSpedon was to devise a schedule under which the diesel engines, which power small trucks that drive along the rails, would be shut down while the tunnel is full of workers.

“I don’t understand that,” said Stan Rhyu, chief engineer for Cal/OSHA’s division of mining and tunneling. “Is the truck going to run itself?”

The trucks are used to haul tools and construction supplies to workers in the tunnels.

Heavy construction has been completed in the subway and contractors are now concentrating on finishing work that includes tiling and installation of elevators, escalators and other electrical fixtures.