Expert Says Toxic Gas Plant Risks Overrated : Toxicologist Assails Air Pollution Control Officials at Phoenix Corp. Hearing

A prominent toxicologist and former federal environmental official charged Friday that San Diego County air pollution officials violated traditional methods of risk assessment when they concluded that a La Mesa toxic-gas manufacturer was a threat to public health.

Dr. Burton Goldstein, hired by Phoenix Research Corp. to testify on their behalf, told a county hearing board that even the worst conceivable accident at the Alvarado Road plant would not harm people in the residential and commercial area nearby.

“It’s really a complete lack of understanding of how you set standards and why you set them,” Goldstein said of the analysis by county and state health officials. “You’ve flunked Toxicology 1. I wouldn’t let a graduate student write that.”

Goldstein’s testimony came on the first day of a hearing in which Phoenix is appealing the decision by the county Air Pollution Control District to deny the firm permits to operate--a decision that could result in the shutdown of the 13-year-old plant.

The air pollution district staff concluded Dec. 31 that Phoenix had been unable to prove that an accidental release of arsine or phosphine gas would not endanger public health and safety. The agency moved Jan. 5 to close the plant but was enjoined by a judge pending Phoenix’s appeal.

The appeal is being heard by the Air Pollution Control District hearing board.

On Friday, Phoenix presented Goldstein, chairman of the Department of Environmental and Community Medicine at the New Jersey College of Medicine and Dentistry and a former assistant administrator of the U.S. Environmental Protection Agency.

Goldstein contended that the district staff exaggerated the health risk posed by the plant by taking an accepted level beneath which one-time arsine exposure is considered safe and adding a “margin of safety” of 100.

Goldstein, who helped compute accepted levels for emergency exposures to other chemicals through his work on various National Academy of Sciences boards, said that a margin of safety is appropriate only when computing safe levels for chronic exposures and is never used for one-time exposures.

He said scientists use a margin of safety to account for “repetitive effects” such as the accumulation of a chemical in the body and sensitization to the chemical over time. He said that neither effect would apply in a one-time emergency and that neither occurs with arsine.

Goldstein supported Phoenix’s computations and conclusion that an accident at the plant would not harm public health.

The district staff has stood by its use of the hundredfold safety factor, noting that the traditional level was set based on studies of mice, not humans, and that it was developed for a group of healthy, active members of the military.

Further, the staff has said, the traditional level is one at which health effects are low and reversible. They say they are required under law to find a level at which there are no health effects and therefore have applied the safety factor.

As a result, Phoenix and the district staff differ dramatically in their assessment of the health effects of a “worst-case scenario” at Phoenix. In that scenario, 130 pounds of gas would be released--an accident Phoenix says has a likelihood of occurring once in 37 million years.

Phoenix, which is owned by Union Carbide Corp., moved to La Mesa in 1973 and apparently has operated without a serious accident since then. Although there have been small mishaps within the plant, company officials say there has never been an accidental release of either gas.

Arsine and phosphine gases, widely used in the semiconductor industry, are unusually toxic. Some scientists say that exposure to as little as 500 parts per million of arsine would be lethal almost instantly.

In January, 1986, in response to publicity and public pressure for the Phoenix plant to move, La Mesa Mayor Fred Nagel asked Union Carbide to relocate its operation. Union Carbide officials agreed to move before their lease expires on Jan. 1, 1991.

In the meantime, the air pollution district learned of the plant’s existence and informed Phoenix officials that they needed a permit to operate. Phoenix applied in early 1986 and the district staff finally denied the permit Dec. 31.

The appeal hearing is to continue March 10.