Lab Detects Glitch in Test Used on Ill Firefighters

An investigation into a fire that sickened dozens of Los Angeles County firefighters has prompted one of the country’s top toxicology labs to determine that one of its tests might wrongly indicate exposure to a dangerous herbicide.

As a result, experts believe that, contrary to earlier indications, there were no toxic amounts of chemicals present at the mysterious fire last fall that burned for two weeks on the site of a former oil refinery in Newhall.

“You’re not seeing a level of unusual chemicals that would cause a problem,” said Dr. Joseph Fedoruk, who has conducted an extensive, 11-month review of firefighters involved in the blaze. “There isn’t an unusual pattern of chemical toxicity.”

The lab in question, Pennsylvania-based National Medical Services, is contacting medical officials throughout the country to warn of problems with the test, which confuses caffeine and cyanazine, an herbicide suspected of causing birth defects and cancer.

Although the numbers are unclear, at least 100 people nationwide, including the Los Angeles firefighters, have tested positive in the last two years for exposure to the herbicide, which is being taken off the market at the end of this year because of its potential danger.

Lab officials said they have corrected the problem, which they believe applies only to tests conducted after January 1998. The trouble was traced to a gas chromatography machine in use at that time to perform the test.

“For a lab like ours, this is significant,” said Robert Middleberg, the laboratory director for the company, which has frequently provided test results for law enforcement agencies and experts to use when testifying in court trials, including the O.J. Simpson trial. “It impacts on people’s lives. Whether it’s one or a hundred, it’s very important to us.”

At least 16 of the 200 Los Angeles County firefighters who battled the blaze at Santa Clarita Greenwaste tested positive for high levels of cyanazine in their bodies, along with other chemicals. The lab has concluded the tests were mistaken.

All told, more than 60 firefighters filed workers’ compensation claims stemming from the blaze. Tests from blood, water, soil and smoke showed trace amounts of a variety of dangerous chemicals, including arsenic, lead and phenol.

Last summer, however, Fedoruk told firefighters that none of those chemicals were present in high enough amounts to cause harm. But he continued to puzzle over tests showing high levels of cyanazine in the firefighters’ blood.

As a result, he asked National Medical Services to review its testing procedures. That review showed that caffeine can fool the test, producing a false positive.

Fedoruk, Middleberg and other experts said the discovery means the firefighters almost certainly were not exposed to dangerous amounts of the herbicide, manufactured by DuPont Co. under the trade name Bladex. Instead, they believe that a cup of coffee or other food containing caffeine caused the test to falsely report cyanazine exposure.

Fedoruk said smoke inhalation may have sickened many of those who fought the blaze. He said he planned to report final results to the county later this year.

But a doctor who has treated many of the firefighters said the test’s problems only further confuse whether the firefighters were exposed to the herbicide. He said many of the firefighters don’t eat or drink anything containing caffeine.

Gary Ordog, chief toxicologist for Henry Mayo Newhall Memorial Hospital in Valencia, said at least 100 firefighters tested positive for exposure to differing levels of cyanazine. He said the chemical, mainly used to treat crops, may have been present at the dump, which collected yard clippings and green waste from throughout Los Angeles.

The firefighters affected by the blaze have complained of a variety of symptoms, including debilitating fatigue, headaches and impotence. One firefighter remains on medical leave.

“I still think they have cyanazine, especially the one who never had coffee,” Ordog said. “I don’t know how invalid those results are.”

Chemists and toxicologists said problems with false positives happen occasionally. For instance, Salt Lake City-based ARUP Laboratories, another of the country’s leading toxicology labs, discovered that one of its tests falsely reported a person had taken a narcotic called meperidene. The error was quickly corrected, according to an ARUP official.

With more than 20 million compounds recognized by chemists, confusion is bound to happen in such tests, several experts said.

“It’s not unusual for there to be some bumps along the road in identifying things based on laboratory tests,” said Michael O’Malley, an herbicide expert and medical consultant to the state’s Department of Pesticide Regulation.

National Medical Services is one of the few labs in the country that performs the test for cyanazine, and such requests make up less than 1% of their analyses.