More than a million people every year die from malaria. In attempts to control this mosquito-borne killer, many countries still use DDT, spraying houses with the insecticide. Some researchers, however, have argued that exposing humans to DDT poses health risks. They want to ban DDT and introduce newer, safer products. Yet a number of these malaria-ridden countries, especially in Africa, can't afford the alternatives. Furthermore, certain regions may house mosquitoes that are resistant to the alternative chemicals. These issues form the basis of a debate published in this week's issue of the British Medical Journal.

On one side, Amir Attaran and Rajendra Maharaj of Harvard University assert that spraying DDT is an inexpensive and highly effective method of combating malaria and that it has been approved by the World Health Organization. Moreover, they report, the public health benefits vastly outweigh DDT's purported health risks, which have never been proved. Richard Liroff of the World Wildlife Fund takes the opposing position, arguing that DDT should be phased out and replaced by safer alternatives. According to Liroff, research suggests that being exposed to DDT early in life might lead to harmful effects. What's more, he notes, many alternatives to DDT have been used with great success. Enabling the poorest countries to make the shift, however, would require financial and technical assistance from developed countries, he notes. With the United Nations Environment Programme meeting in Johannesburg this week to discuss phasing out DDT, Liroff's vision may soon come to pass.