By Hillel Aron
By Joseph Tsidulko
By Patrick Range McDonald
By David Futch
By Hillel Aron
By Dennis Romero
By Jill Stewart
By Dennis Romero
Within three weeks, independent analysis of the tissues of dead animals found in the treated areas demonstrated that more than 98 percent contained detectable residues of the poisonous compounds. Further investigation in Texas and Louisiana showed that the bird population in those states had declined more than 85 percent since the spraying. A subsequent report, called ”The President‘s Study on the Ecological Effects of Pesticides on Nontarget Species,“ found hundreds of dead animals, ranging from mammals and birds to reptiles and fish, on a handful of Louisiana farms. On one four-acre stretch of land, according to the report, ”47 days after treatment, no live animals were seen or heard on the plot, and a total of 38 dead animals had been found.“ In her 1962 environmental chronicle Silent Spring, Rachel Carson described the fire-ant campaign as ”an experiment so expensive in dollars, in destruction of animal life, and in loss of public confidence in the Agriculture Department that it is incomprehensible that any funds should still be devoted to it.“ By the end of 1962, dieldrin and heptachlor had been phased out. During the five-year experiment, 20 million acres had been treated, while the fire ant had increased its area of infestation from 90 million to 126 million acres.
Meanwhile, in Gulfport, Mississippi, at the USDA Methods Development Laboratory, a team of chemists had created a new compound called Mirex, which -- mixed with soybean oil and corncob grits into an appetizing swill -- disrupts the ant’s nervous system very slowly and is regurgitated through the colony, eventually making its way to the queen. Orville Freeman, the secretary of agriculture from 1961 to 1969, hailed it as the ideal pesticide. ”It has no harmful effect on people, domestic animals, fish, wildlife or even bees,“ he said. ”And it leaves no residue in milk, meat or crops.“ In 1962, the USDA began applying Mirex in large quantities and soon announced that, following several applications, the miracle poison would entirely eradicate the fire ant in the U.S. Over the next 15 years, Congress alone spent close to $100 million on the Mirex program.
Once again, a toxin had not been tested sufficiently. Mirex, it turns out, with a melting point of 349 degrees Celsius (it was patented both as a pesticide and a flame retardant), metabolizes very slowly and moves up the food chain virtually unchanged. Studies conducted more than a decade later found that 21 percent of all human inhabitants of treated areas showed positive residues of Mirex in their body fat. Aside from its devastating effect on plants and animals -- the chemical was later shown to be carcinogenic -- Mirex had exterminated every insect in the treated area. In the long run, the USDA‘s new tactic had actually strengthened the fire ant’s domination by wiping out all of its natural competitors.
In 1969, Congress passed the National Environmental Policy Act, President Richard Nixon created the Environmental Protection Agency, and the Environmental Defense Fund, the first federal agency formed to legally pursue environmental problems, brought suit to terminate the USDA‘s fire-ant program. The case was popularly known as EPA vs. Allied Chemical (the sole producer of Mirex). Officially, it was an investigatory hearing held to determine whether or not the registration of Mirex should be cancelled or amended and was held before the National Occupational Health and Safety Review Commission in Washington, D.C. The hearing marked a profound shift in the way Americans perceived the environment; for the first time, the unbridled use of powerful pesticides had been seriously questioned. The EPA issued a cancellation order for Mirex soon after the hearing began, but Allied Chemical protested the decision, and the proceedings lasted another six years. During that time, the EPA hired a team of scientists that ended up rebuking the USDA for its obsession with chemical warfare.
Walter Tschinkel was a young Ph.D. at that time who had primarily been involved in researching beetle communication patterns. He was also a key witness in the trial against the USDA. ”I was relatively new to fire-ant research then,“ he says. ”Most of the information I had was the USDA’s data on all these important biological questions, which was public information, I suppose. And I analyzed those [data] very carefully, in a way the USDA hadn‘t.“
Tschinkel’s arguments before the committee totally invalidated the idea of eradication. He showed that the fire ant was far too engaged with the environment, too specialized and too elusive for a large-scale general-application poison to have any lasting effect on it. He presented a chart, called a ”Dose Killing Curve,“ which showed that without unleashing an incredible amount of toxins into the environment, a substantial number of colonies would always be missed. There were simply too many of them. ”[When] the concept of eradication was embraced by the USDA and its allies,“ Tschinkel says, ”it was already far too late.“ By the end of the hearings, Allied Chemical had sold its plant to the state of Mississippi for $1. Dreams of eradication died with the Mirex program.
After the USDA ceased funding eradication efforts, farmers gradually learned to live with the pest, although the threat remained the same. Indeed, with the benefit of hindsight, the perceived direness of the threat becomes something of a mystery. Before the initial campaign to wipe out the fire ant began in 1957, only two of the infested states had listed it among their 20 most important insect pests, and these states had placed it near the bottom of the list. Nevertheless, the species ended up being marked for wide-scale eradication. When that dream died, it was replaced with the more economically promising alternative of managing the fire-ant population in perpetuity.