As the U.N. drafts a treaty that could ban DDT worldwide, many health officials are protesting that such a ban would devastate efforts to control malaria in some developing nations. DDT, one of 12 highly toxic chemicals known as persistent organic pollutants that the U.N. plans to eliminate, is sprayed in small amounts on the interior walls of homes in some developing countries to repel malaria-carrying mosquitoes. More than 370 health officials in 57 countries are arguing that this use be allowed to continue, at least until industrialized countries conduct more research on expensive alternatives and help developing nations pay for them. The World Wildlife Fund and Physicians for Social Responsibility argue that even small amounts of DDT are harmful to the environment and potentially humans as well. Jim Willis, director of chemicals for the U.N. Environment Program, said some type of public health exception to a DDT ban is likely.