DDT is a cheap way to eliminate insects that threaten crops and people-including mosquitoes that spread malaria. Because it accumulates in the food chain and causes harm to humans and animals, its use has been banned in the United States since 1972. How- ever, 23 nations continue to use it for malaria control, although most countries no lon- ger use DDT for agricultural purposes. Alternative pesticides-such as pyrethroids-are almost two to three times more costly. By 1999, only three nations-China, Mexico, and India-still produced and exported DDT. However, when the United Nations consid- ered a worldwide ban on DDT as part of a plan to minimize the use of 12 toxic chemicals ("persistent organic pollutants"), some members of the public health community were alarmed.

There was a resurgence of mosquito-borne malaria, with some 300 to 500 million new cases a year. Drugs to treat malaria are expensive and increasingly ineffective against the disease. Use ethical theory to articulate a response to this dilemma.