BOISE, IDAHO - Before fleeing their home in the belief it was killing them, before the lawyers, the expert witnesses, the dead dog and the bankruptcy, Bill and Laurie Enger had just one question: Why is this happening?
Laurie Enger's numbed brain offered no help. Nor could anyone else explain why, in those spring days in 1994, her pounding skull forbade sleep or why her lungs pumped out fluids. Or why, when she walked down her hallway, she careened off the walls as if she were a drunk on a rolling ship.
The Engers later believed they had found their answer: They had been poisoned by Dursban, the most widely used insecticide in America.
The Engers say exposure to Dursban, sprayed in their home by Orkin Exterminating, ruined their lives and finances. Their lawsuit against Orkin was settled without definitely establishing a link between their health problems and the insecticide, but their story is an example of what regulators say are the dangers posed by Dursban.
The mounting problems with the bug killer have led the Environmental Protection Agency to target the insecticide for what could be dramatic restrictions.
The EPA changes - affecting Dursban's hundreds of uses, from termite control to flea collars - could come within a few weeks.
Orkin already has stopped using Dursban for residential jobs unless homeowners specifically request it.
In the Engers' case, an expert the couple hired concluded that Orkin misused Dursban in their home and that residues of the insecticide were 3,400 times higher than levels considered safe. But thousands of reports of poisonings in EPA files come from Dursban use well within the current rules. The agency's own scenarios of how Dursban is used in homes and yards conclude that the insecticide poses a serious risk, especially to children.
Orkin, which denied any wrongdoing in the Engers' case, last month paid $175,000 to settle the suit. Because the Engers were in bankruptcy, they did not get the money, which went to pay their creditors and legal fees.
In court papers, Orkin said the Engers, who had previous health problems, could not link their suffering to the company's actions.
The Engers' doctors have concluded that both are permanently disabled from toxic exposure but acknowledge they cannot connect the health problems to the Dursban sprayed by Orkin.
Dursban is a cousin of the deadly nerve gas developed by German scientists during World War II. Its active chemical is a nerve agent called chlorpyrifos. Dursban and similar insecticides, called organophosphates, kill by depleting the body of enzymes essential to normal operation of the nervous system.
Scores of lab tests over the years show Dursban can enter the body through the skin or the lungs. As with all organophosphates, Dursban at low levels of exposure causes dizziness and nausea. As exposures increase, victims can suffer lasting neurological problems. At higher levels, Dursban will kill.
What sets Dursban apart from similar bug killers is its potency and the wide array of products in which it's used. EPA records show Americans used 20.9 million pounds of Dursban last year. Its manufacturer, Dow AgroSciences, says 70 percent of Dursban is used to kill termites. But other Dursban products are used outdoors on lawns and shrubs, and indoors in offices, schools, hotels, hospitals and restaurants. Dursban also is used frequently in pet flea collars.
These opportunities for exposure have led to about 7,000 accidental poisonings every year involving Dursban and other chlorpyrifos-based products - more than any other insecticide of its type, EPA reports say.
The EPA is now considering ways to curb the insecticide use both on crops and for residential use. The agency concluded typical uses - including Dursban use on lawns, in cracks and crevices inside the home, and in pet collars - posed too great a health risk, especially for children.
New York's attorney general called for a ban on Dursban earlier this year after a Rotterdam, N.Y., woman miscarried twice and her husband and 3-year-old son experienced health problems that they allege stemmed from a 1996 Dursban spraying for termites in their home.
The Engers came to Idaho after 20 years in southern California. In Boise, they marketed portable painting systems to cover graffiti and dreamed of selling out to a national or regional paint company.
Meanwhile, they had an everyday but pesky problem in their house: ants. One of their two daughters mentioned that ants in their house looked like carpenter ants, wood eaters that are the termites of the Northwest.
To deal with the problem, Laurie plucked Orkin Exterminating's name from the Yellow Pages.
Orkin is one of the biggest and best-known names in the exterminating business. Owned by Atlanta-based Rollins Inc., the 99-year-old Orkin serves 1.7 million customers through more than 400 branches in North America. With Orkin as its primary business, Rollins reports annual revenues of $586 million.