U. S. News and World Report on Dursban - Business & Technology Section - 11/8/99:
The stuff in the backyard shed --- The pesticide is effective and sells like mad. But is it safe for everyone?
BY JIM MORRIS

Every morning over a period of several weeks in 1971, 16 inmate volunteers reported to the hospital at the Clinton Correctional Facility in Dannemora, N.Y. Under the supervision of two scientists and a physician, they were divided into four groups. Three of the groups received pills containing different doses of the pesticide Dowco 179, made with a little-known nerve poison called chlorpyrifos. One received placebos. The prisoners' blood and urine were analyzed, and they were monitored for signs of distress.

By March of 1972, the results of this curious experiment were in. Although 12 of the inmates were fed chlorpyrifos, none became violently ill. Volunteer No. 3, in the highest-dose group, "complained of a runny nose, blurred vision, and a feeling of faintness" but was treated for a cold and recovered. All four members of that group also experienced a sharp drop in levels of an enzyme called plasma cholinesterase–evidence of toxic insult.  But the readings were back to normal four weeks after the dosing ended.

At this point, the study's sponsor, the Dow Chemical Co., had two options: step back and ponder the safety of chlorpyrifos, which it began selling in 1965, or forge ahead and try to grab a bigger share of the lucrative pesticide market. Dow chose the latter, while continuing to test. Sales grew steadily. Marketed by a subsidiary under the names Dursban (for structures) and Lorsban (for agriculture), the pesticide was being applied 20 million times a year in homes, schools, and offices by the 1990s.

Made by Indianapolis-based Dow AgroSciences, chlorpyrifos is the active ingredient in about 1,000 products, including Ortho's Flea-B-Gon and Spectracide's Dursban granules. It dispatches termites, fleas, cockroaches, and other vermin with cold efficiency. Dow AgroSciences earns upward of $100 million a year from sales of the pesticide and stands firmly behind it. "This compound is safe as used, according to the label," says Craig Barrow, director of science policy and regulatory affairs. Barrow says it takes a "sledgehammer" dose to inflict harm.

A U.S. News investigation presents a more complicated picture. Since June 1992, Dow AgroSciences, a predecessor company called DowElanco, and other pesticide manufacturers have sent the Environmental Protection Agency some 7,000 reports of adverse reactions to chlorpyrifos. An EPA analysis found that the chemical was suspected in 17, 771 incidents reported to U.S. poison-control centers between 1993 and 1996. More than half the cases involved children under 6. In a draft report released last week, the EPA said that those who come in contact with the product in its granular and powdered forms–whose dust is easily inhaled and absorbed through the skin–could receive up to 100 times the safe amount. Dow AgroSciences says the document is riddled with errors and omits important data.

This much, at least, is certain: Chlorpyrifos is nearly everywhere. A survey of 1,000 Americans in 1994 found that 82 percent had its residue in their urine. A survey of 46 California school districts in 1997 found that almost half routinely applied pesticides containing chlorpyrifos. In New York the same year, Dursban Pro was the most popular bug killer: State records show that 3.5 million pounds and 665,000 gallons were applied.

New studies suggest that chlorpyrifos poses a particular threat to the developing nervous system, attacking it in ways that can lower intelligence and cause behavioral problems. It may be more toxic in combination with other chemicals than alone, or more toxic in repeated small doses than in a single large one. "It should not be used inside the home," says Mohamed Abou-Donia, a professor of pharmacology and cancer biology at Duke University.

Dow AgroSciences has spent more than $100 million on 3,600 studies that suggest chlorpyrifos is harmless when properly applied. Why, then, has it elicited 274 lawsuits since 1990? "It's been the biggest kid on the block for a long, long time," says Guy Relford, the company's global legal counsel. "Historically, [it has been] one of the most prevalently used insecticides in the world, and when you're out there in the marketplace  like that, then you're going to be a target." Relford can draw from an impressive  pool of scientists. There's Rudy Richardson, Dow professor of toxicology at the University of Michigan, who says: "Caffeine will kill you at the same sort of dose that chlorpyrifos will kill you, and you don't hear too much conversation about banning caffeine from beverages." Richard Kingston, an assistant professor of pharmacology at the University of Minnesota, examined 36,183 known and suspected chlorpyrifos exposures called in to poison-control centers over a 10-year period. His conclusion: Nearly 96 percent "resulted in no significant health effects."

Anecdotal evidence. Others aren't so sanguine. At the EPA, health statistician Jerome Blondell says his figures on individuals exposed to chlorpyrifos–and other organophosphate pesticides like malathion–might be low because not all exposures are reported to poison centers. And the adverse-reaction reports filed by the manufacturers include worrisome anecdotes like these:

"Home interior sprayed for carpenter ants. Dursban used while children were present.  Lady re-entered in three hrs.; headache, nausea, dizzy . . . ."

"Lady had two serious reactions to Dursban in 1988 and 1998. Electric feeling through torso like a seizure, sleep disruption, deadened nerves."

"Flea & tick collar was chewed by dog; dog died."

U.S. News has spoken with more than a dozen people who believe that chlorpyrifos has made them or other family members chronically ill. Hours after the inside of her house in Burnsville, Minn., was sprayed for fleas with Dursban in 1991, a still-ailing Diane Lang thought she was going to die. "I hurt so bad all over. My head was just pounding with a headache like I'd never experienced. Shafts of lightning would just go through my vision.  I was confused." There are many similar stories.

Tragic–but not our fault, responds Dow AgroSciences. The chlorpyrifos exposures in all these cases, Relford says, were well within the "safe zone." But what if the zone isn't safe for everyone? New research supports the notion that there is a hypersensitive minority, susceptible to quantities of chlorpyrifos that wouldn't faze the average person.   In  experiments on mice bred without a crucial pesticide-fighting enzyme, a team from the University of California-Los Angeles and the University of Washington noted a dramatic increase in sensitivity to an oxidized form of chlorpyrifos. It's a concept the EPA must bear in mind as it struggles to carry out its regulatory duties: Is this substance short-circuiting some people's brains even as it snuffs out bugs?

The origins of chlorpyrifos can be traced to the late 1930s, when the German conglomerate IG Farben developed the organophosphate pesticides tabun and sarin. Appropriated by the Nazis as prospective weapons during World War II, the compounds cause symptoms ranging from blurred vision to asphyxia. All organophosphates inhibit cholinesterase, an enzyme that regulates nerve transmission in the body. The result can be overstimulation of the nervous system; in extreme cases, "you can't run, you can't walk, you can't breathe," says Janette Sherman, a physician in Alexandria, Va. "That's the way it kills the insect."

Dow came out with chlorpyrifos in 1965, just as DDT and other pesticides were falling into disrepute. The EPA banned DDT in 1972, opening new markets for organophosphates, but it wasn't until 1988, when the agency blackballed the widely used termite-killer chlordane, that sales of chlorpyrifos took off. The chemical was effective, cheap, and seemed fairly benign.  But there was already a substantial–and troubling–body of knowledge on organophosphates. In 1930, during Prohibition, 50,000 Americans who drank an alcoholic extract of Jamaica ginger experienced numbness of the arms and legs, followed by either temporary or permanent paralysis. The U.S. Public Health Service blamed the epidemic on triorthocresyl phosphate, used to cut the strong ginger taste. Dow's experiment on the New York inmates–limited  though it was by lack of follow-up–yielded more clues. The runny nose, blurred vision, and faintness suffered by Volunteer No. 3 were dead giveaways, says David Wallinga, a senior scientist with the Natural Resources Defense Council. "That's what people get when they get poisoned."

Limited withdrawal. Under pressure from the EPA, DowElanco agreed in 1997 to  withdraw the compound from a few specialized markets, such as indoor total-release foggers and pet shampoos. But the EPA didn't touch the chemical's main residential and agricultural uses. "The agreement with Dow is inconsequential in terms of the overall risk to public health," says Jay Feldman, executive director of the National Coalition Against the Misuse of Pesticides. Feldman and others find it even less palatable in light of  allegations that the company has hidden or misstated evidence of its product's toxicity. In 1994, DowElanco agreed to discontinue what the New York attorney general characterized as deceptive claims in a Dursban brochure. In 1995, the EPA fined the company $876,000 for belatedly reporting 288 possible adverse reactions to chlorpyrifos. In June, the agency alleged that Dow AgroSciences waited too long to report ailments of a Kansas couple whose home had been treated for termites with Dursban TC.

Dow AgroSciences gives not an inch on any of these matters. Relford, the corporate counsel, says the statements in the supposedly deceptive Dursban brochure were grounded in science. The late submission of the 288 cases occurred because the company and the EPA had different interpretations of federal law. DowElanco struck the 1997 deal with the agency not because it believed consumers and animals were being hurt by chlorpyrifos, but purely as a precaution. Dow AgroSciences could make the pending complaint go away by paying a modest $5,000 fine, but it won't do so as a matter of principle.

Even in the fractious world of environmental health, the discord over chlorpyrifos is striking. Duke's Abou-Donia is convinced that chlorpyrifos can ravage the developing nervous system under common exposure scenarios.  "A pregnant woman should never be exposed to this chemical," he says. But Dow AgroSciences neurophysiologist Patrick Donnelly argues that Abou-Donia is dosing his laboratory animals with unrealistically high levels, which are "irrelevant for the purposes of . . . regulatory decision making."

The EPA is expected to complete its lengthy reassessment of chlorpyrifos next year and may impose further restrictions on the chemical. "We are certainly not bashful," says Deputy Assistant Administrator Stephen Johnson.  "We will take action to mitigate a risk."

Trend against suits. Absent an EPA clampdown, detractors of chlorpyrifos will have to make their case in court. So far, they haven't had much luck:  Of the 16 Dursban lawsuits resolved this year, 15 were dismissed and one was settled for $1,000. Attorney Stuart Calwell, of Charleston, W.Va., bucked this trend in 1995, securing an eight-figure settlement for Joshua Herb, a paralyzed Charleston boy who had been exposed in utero to Dursban and another organophosphate, propetamphos. DowElanco had been prepared to go to trial, Calwell says, until animal tests performed by Abou-Donia showed that chlorpyrifos, when combined with the other chemical, caused "catastrophic  destruction" of the nervous system in lower doses than it would have alone.  From a tactical standpoint, Dow AgroSciences counsel Relford doesn't regret the decision to settle: "We were facing a jury trial in West Virginia, in state court, involving a  51/2-year-old little boy who was a paraplegic and respirator-dependent," he says. "And we couldn't look at that case . . . and not have a huge amount of sympathy for Joshua Herb." Nor, presumably, could the jury. Relford worries, however, that the payout might be misinterpreted as an admission that chlorpyrifos is hazardous. "You won't see another settlement like that," he says.

Despite the plaintiffs' poor litigation record, lawsuits continue to trickle in. One says that on the afternoon of July 31, 1993, Joey Walker applied a granular fire-ant killer called Green Light to his yard in Liberty Hill, Texas. Dressed in a T-shirt, jeans, and boots, Walker was using a hand-held spreader–just as the label instructed–and inhaled the compound, absorbed it through his sweaty skin, or both. That evening, he collapsed on the sofa, complaining of flulike nausea, fatigue, and headache. In April 1994, he  suffered a grand mal seizure while watching his oldest son play Little League baseball. "He turned blue," his wife, Margaret, recalls. "All his muscles drew right up, like the Incredible Hulk." Walker was in and out of hospitals for 15 months. In August 1995, he was admitted to a nursing home, where he remains in a vegetative state. Walker had used Green Light without incident the year before he got sick. Does this mean, as Relford says, that "hypersensitivity just doesn't hold up"? Or does it mean, as Abou-Donia theorizes, that the effects were cumulative? Walker, now 43, is oblivious.  "He can look around," his wife says, "but we're not sure what he sees."

Many people use chlorpyrifos, of course, with no repercussions. A blood test confirmed that Walker has extremely low levels of paraoxonase, an enzyme that offers protection against chlorpyrifos. The trouble is, there's no practical way to know–before a potentially devastating reaction–just who's in this vulnerable group. It may, for instance, include children like Christie and A. J. Ebling of New Albany, Ind., who developed seizures, learning disabilities, and incontinence after a pest-control service repeatedly sprayed their apartment with Dursban and an organophosphate mixture called Creal-O in 1994. "The fact that this occurred in two children simultaneously is pretty hard to ignore," says Roger Pardieck, the family's attorney in a lawsuit against Dow AgroSciences. "Their doctors have looked for every other possible explanation, and there is none." The company is contesting the suit.

A.J., 6, has been seizure-free for 2 1/2 years and is finally potty trained.   Nine-year-old Christie is another story. "She's gone downhill," says Cindy Ebling, her mother. On the afternoon of August 11, she was admitted to a hospital following a round of intense seizures. "I found her face-down in her eggs," Cindy Ebling said in the hospital room that evening. Christie sat on her bed a few feet away, gaping at a visitor, drooling, and hooting as she struggled to assemble a simple puzzle. "I have a hard time even looking at Christie anymore," says her father, Todd Ebling, recalling how bright she once was.

BUG OFF - Looking for a safe alternative

Organophosphates are effective against pests like termites and citrus rust mites; Lorsban alone is used on up to 10.5 million acres of cropland every year. But some longtime users have changed course.

Fremont, Mich.: Gerber Products Co., the nation's largest manufacturer of baby food, has told its fruit growers to phase out organophosphates. Last year, all of Gerber's peaches were protected with mating-disruption pheromones, which inhibit insect reproduction without chemicals.

Chicago: Three years ago, cockroaches were tormenting residents of the 1,000-unit Henry Horner public housing development. The response from the Chicago Housing Authority? Fog and spray. The Safer Pest Control Project, in a one-year pilot program, replaced aerosol compounds with gels and pastes. Cracks were caulked and residents asked to cover trash. The roach population plummeted.

Northmont, Ohio: For decades, the Northmont City School District near Dayton sprayed for insects, often with un- satisfactory results. In 1995, the district hired Michigan consultant Steve Tvedten, who vanquishes vermin with talcum powder, borax, carbon dioxide, and natural enzymes. Tvedten's remedies did the trick. -J.M.
 

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Post Script:
"The availability of the Preliminary Risk Assessment for Chlorpyrifos was recently announced in the Federal Register.  The complete assessment plus industry comments are available on the EPA web site (all 1300 plus pages of it) for review by using Acrobat reader.  The site address is: http://www.epa.gov/pesticides/op/chlorpyrifos.htm .  This is the most
complicated review performed and published to date.  The primary summary document is in the section titled health effects and is the "Health Effects Preliminary Assessment" which is 67 pages long.  There are 16 appendices to this document including the Incident Review Update which is 26 pages long. By examining the primary document and noting the Margin of Exposures that are low (less than a 100 for occupational or less than 300 for residential exposures) you
can determine where the most concern is.  Most of the concerns were related to occupational and residential exposures among handlers, not from dietary exposures".