Independent Study Urged of Health Risks From Gas in Subway : Red Line: MTA commissioner wants doctors to look at foul-smelling fumes in tunnel. Reports show that levels can be high enough to cause headaches, nausea.

The potential health risks posed by a sulfur-smelling gas that is causing complaints from passengers and train operators in the Downtown Los Angeles subway should be examined by physicians who are independent of the project, a transit commissioner said Tuesday.

“I’m going to suggest getting some independent physicians to study this,” said Nick Patsaouras, an engineer who serves on the board of the Metropolitan Transportation Authority. Patsaouras said he will make his recommendation today at an MTA board meeting.

The recommendation comes as state and county health officials opened a review of the problem. Based on gas readings collected by the MTA and on interviews, The Times reported Saturday that volumes of the substance, hydrogen sulfide, typically reach levels that public health officials say can cause headaches, nausea or malaise.

Physicians with the California Environmental Protection Agency and the Los Angeles County Health Department said Tuesday they would jointly examine the problem. An MTA spokesman said the agency was notified Tuesday that health authorities are investigating.

The transit authority will “cooperate with them and provide whatever documentation they need,” said Rick Jager, an MTA spokesman.

Dr. James W. Stratton, a chief deputy director of the state EPA, said he will lead the probe, along with Dr. Paul J. Papanek of the county health department’s toxics epidemiology unit.

“We will . . . be rendering some opinion of what we think of it” and recommending possible corrective action, Stratton said.

The MTA is expected to release the findings today of a separate panel that the agency appointed to examine the structural soundness and durability of the subway’s concrete tunnel walls.

Soil studies published in advance of the subway construction noted the existence Downtown of hydrogen sulfide, a gas common in areas of former oil exploration. According to the MTA, levels of hydrogen sulfide typically reach concentrations in the subway tunnels and stations of 5 to 8 parts per million.

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Federal health standards warn that respiratory or nervous system problems can result after 10 minutes or more exposure to hydrogen sulfide at concentrations of 10 parts per million or greater. The gas can be lethal at 300 parts per million.

Physicians contacted Tuesday said that studies over the past five years appear to counter previous assumptions that exposure to hydrogen sulfide at lower levels poses little cumulative health risk.

Dr. Kaye H. Kilburn, a professor at USC School of Medicine who is studying the impact on oil refinery workers and residents of trace levels of hydrogen sulfide, said concentrations of 5 p.p.m. to 8 p.p.m. are cause for alarm.

“The truth of the matter is that it’s a serious problem,” Kilburn said. She added that even at 2 p.p.m., “it’s a thousand times too high to be safe. It kind of makes me quiver.”

Herbert Venable, a biologist with the National Institute of Occupational Safety and Health, said he believes the MTA should immediately install sensors at the lowest elevations of the subway structures to get the most accurate readings possible. Although hydrogen sulfide is heavier than air, the MTA now relies on sensors that are at the tops of the tunnels and stations.

“If you want to get a real handle on what you’ve got, you’ve got to get real low,” Venable said. “I don’t want to raise concerns unnecessarily, but the nature of hydrogen sulfide is to be fairly sneaky.”

Two months ago, MTA officials announced that they would delay construction of a 2.3-mile Red Line extension because of concerns about hydrogen sulfide concentrations in the general area of Olympic and Crenshaw boulevards.