‘Far From the Worst-Case Scenario’ : Expert Blasts Estimate of Toxic Gas Plant Risk

A leading expert on the medical effects of toxic gases Monday criticized the worst-case scenario being used by San Diego County air pollution officials to assess the health risks posed by Phoenix Research Corp., a La Mesa firm that manufactures two of the deadliest gases used in industry today.

Dr. Joseph LaDou told the Air Pollution Control District’s board of directors that the fictional episode being used to forecast the worst possible consequences of an arsine gas release at the company was, in his view, radically optimistic.

“I would argue that this is far from the worst-case scenario you could have as a result of arsine exposure,” said LaDou, acting chief of the Division of Occupational and Environmental Medicine at the University of California, San Francisco. “In fact, I’d say this is a best-case scenario.”

Missing Contingencies Cited

Specifically, LaDou said the alleged worst conceivable accident presented by Phoenix officials and embraced by the district staff fails to account for earthquakes, power failures and other glitches that might cause safety equipment to fail should a major gas release occur.

LaDou’s testimony came during an ongoing hearing at which Phoenix is appealing the district’s decision to deny it permits to continue operating.

In December, the district’s staff concluded that Phoenix--which is owned by Union Carbide Corp.--had failed to prove that it could guard against danger to the public health in the event of an accidental release of arsine or phosphine gas.

The agency moved to shut down the controversial, 13-year-old plant on Jan. 5, but a judge’s order prohibited closure pending the firm’s appeal.

In February, the hearing before the district’s three-member board got under way with expert testimony from witnesses called by the firm. One prominent toxicologist hired by Phoenix, Dr. Burton Goldstein, testified that district staff members had exaggerated the health risk posed by the plant.

Goldstein, who is chairman of the Department of Environmental and Community Medicine and Dentistry at the New Jersey College of Medicine and Dentistry, insisted that even the most drastic accident would not harm people in the residential and commercial area near the firm.

Relocation Urged

LaDou’s position could not have differed more.

During the daylong session, the toxicologist--called as an expert witness by the district--repeatedly expressed in no uncertain terms his belief that Phoenix should immediately relocate to an unpopulated area.

“No expert will tell you that arsine, phosphine or other toxic gases should be stockpiled, delivered or manufactured in a congested community,” said LaDou, who also works as a consultant to numerous high-technology companies in the Silicon Valley. “It is simply too dangerous a basic activity for the City of La Mesa.”

In particular, La Dou was critical of Phoenix’s assertion that there would be no deaths from the release of 130 pounds of toxic gas--a “worst-case scenario” that the firm says has a likelihood of occurring once in 37 million years.

Under the firm’s scenario, the gas from a ruptured valve or broken line would be promptly collected by the plant’s ventilation system and released into the atmosphere by a fan that would help dilute its toxicity to a level not hazardous to humans.

But LaDou charged that such a scenario accepts the presence of a fan and “assumes very effective dilution of the gas.”

“I would contend that in any major disaster setting you will be fortunate to have a functioning fan on a building such as Phoenix Research,” he said.

Alternate Scenario

Under an alternate scenario LaDou presented Monday, a release of a much smaller amount--24 pounds--from a spill at a given plant’s loading dock would kill everyone within the immediate vicinity of the facility.

“(At a distance of) five football fields away from the (arsine) cylinder, if you have short-term exposure, I might imagine an occasional survivor,” LaDou said.

Moreover, LaDou said he suspected that occasional emissions of arsine routinely occur at Phoenix--a claim that company officials vehemently denied.

“If (Phoenix shares) any similarities to the electronics industries at all, I can assure you (occasional emissions of arsine have) happened,” LaDou said. During a break in the hearing, he added that such releases frequently occur when gas lines are cleaned--or “purged”--so that new gases can be pumped through them.

“The bottom line is there are a lot of questions about the manufacturing process out there that have not been answered,” he said.

Randall Kelly, manager of the firm on Alvarado Road, said a computer-driven monitor in the plant detects arsine and phosphine emissions beginning at a level of .025 parts per million. No “measurable emissions” have been detected at the plant to date, said the company’s attorney, Betty-Jane Kirwan.

Although board members seemed concerned about LaDou’s criticism of their worst-case scenario, they declined to delve into it, noting that the model has already been accepted by both Phoenix and the district.

No Serious Mishaps

Phoenix moved to La Mesa in 1973 and has operated, quietly and apparently without serious incident, since then. There have been small mishaps within the plant, but company officials say there has never been an accidental release of gas.

Arsine and phosphine are colorless, highly toxic gases widely used in the semiconductor industry. Exposure to as little as 500 parts per million of arsine causes almost instant death by destroying red blood cells.

More than a year ago, La Mesa Mayor Fred Nagel asked Union Carbide to relocate its operation in response to publicity and public outcry. The company agreed to move before the plant’s lease expired on Jan. 1, 1991, but one attempt to relocate to Washington State was aborted, ostensibly because of an unfavorable economic climate in the state.

Meanwhile, the air pollution district has discovered the plant’s existence and informed Phoenix officials they needed a permit to operate. Phoenix officials have challenged the district’s jurisdiction in the matter.