No Observed Adverse Effects: Developing Neurons, Organophosphate Insecticides, and the 1996 Food Quality Protection Act

Physicians are familiar with organophosphates (OPs) as a classic, though obscure, cause of cholinergic poisoning. Many opportunities for human exposure existsixty million pounds of OPs are applied as insecticides to sixty million acres of U.S. land each year, and, until recently, over one-fifth of Americans used these chemicals in their homes. Most physicians, however, still know little about the dangers that these pesticides pose to the developing nervous system. By the late 1980s, toxicologists increasingly recognized that toxicants such as lead and mercury, even at doses well-below the level required to cause symptomatic poisoning, could induce subtle, yet permanent, neurological deficits if the exposure occurred during critical periods of brain development. In the early 1990s, scientists and regulators began to realize that developmental neurotoxicity (DNT), as this phenomenon was called, could also result from OPs. In 1996 Congress passed the Food Quality Protection Act (FQPA), marking a major turning point in the regulation of hazardous chemicals. Prior to the FQPA, the Environmental Protection Agency (EPA) based its calculations of pesticide risk on adults and largely neglected the increased susceptibility of infants and children. The new law took a precautionary stance, protecting the vulnerable neural and physical development of the fetus and child with the inclusion of a 10-X safety factor, and shifting the burden of proof from health advocates to the pesticide manufacturers. The ensuing ten-year battle between health groups, pesticide manufacturers, and the EPA over the laws enforcement now provides an instructive lesson into the complex scientific, political, and economic world of environmental health, and serves as a relatively successful example of effective policy improving public health