Despite the fact that DDT was banned without public health justifications, many people still believe it is dangerous to public health. While Rachel Carson did not rule out some limited use of DDT, she greatly contributed to perceptions that it was dangerous, which advanced extreme approaches like government bans. In a chapter titled, “Elixirs of Death,” she claimed that while DDT might not be toxic in a powder form, it is “toxic” in other forms and when ingested. And she said because it is stored in tissue, its accumulation means that the threat to poison and produce degenerative diseases in organs is “very real.” In the chapter titled “One in Every Four,” she claimed that cancer rates were climbing and would continue to climb because of the use of chemicals, including DDT.

While Carson could offer no definitive science on the issue, she offers anecdotes that imply problems caused by DDT. For example, she describes a man who after spraying for cockroaches using a product containing DDT suffered from hemorrhaging. The man was eventually diagnosed with leukemia, which eventually led to his death. There is no evidence that his illness had anything to do DDT use, but Carson attempts to link the two. She also notes that one researcher gave DDT a “definite rating” as a “chemical carcinogen” based on lab tests that produced tumors in rodents. However, none of Carson’s findings in these chapters amounted to anything more than speculations that offer nothing in terms of scientific value.

Since the findings of the Environmental Protection Agency (EPA) committee in the 1970s that reported no public health problems arising from DDT, there remains no compelling evidence that DDT has produced any ill public health effects. In 1990, an article in the medical journal The Lancet reported: “The early toxicological information on DDT was reassuring; it seemed that acute risks to health were small. If the huge amounts of DDT used are taken into account, the safety record for human beings is extremely good. In the 1940s many people were deliberately exposed to high concentrations of DDT thorough dusting programmes or impregnation of clothes, without any apparent ill effect…In summary, DDT can cause toxicological effects but the effects on human beings at likely exposure are very slight.” In any case, the risks of using DDT should be weighed against the very real life-and-death risks of malaria.

Several studies have attempted to link DDT with some cancers and other problems, but have failed to show a conclusive link. In particular, a number of studies have sought to establish a link between DDT and related pesticides and breast cancer, claiming that these produces disrupt endocrine systems and produce breast cancer. One study claimed to find a link in 1993, but it was deemed not definitive in part because of its relatively small sample size. Subsequent studies of greater scope could not find a link. The National Research Council concluded in 1999, in a report reviewing the “endocrine disruptor” issue, that the original breast cancer study and all the ones published before 1995 “do not support an association between DDT metabolites or PCBs and the risk of breast cancer.” More recently, U.S. researchers produced one of the largest and most comprehensive studies ever on the topic, assessing the impact of pesticides on breast cancers among women in Long Island, New York. This research could not find a link between the breast cancers and the chemicals most often cited as the problem (DDT and other pesticides as well as PCBs).

There has been similar focus on the potential for DDT to impact children through their mother’s breast milk. However, again, there is little evidence of such problems actually existing. Malaria experts Amir Attaran and Rajendra Maharai point out that researchers have not found any detectable health effect on babies from traces of DDT found in breast milk. Moreover, the World Health Organization’s (WHO) Expert Committee on Malaria noted in 1995 that such concerns are not relevant to DDT use for malaria control because they did not find evidence that the use of DDT to control malaria would have any such adverse public health effects. Accordingly, the WHO noted that DDT should remain a tool for controlling malaria despite concerns about its appearance in breast milk.

While the risks of DDT to newborn babies through breast milk exposure are insignificant, malaria presents far greater risks to newborns. The Roll Back Malaria campaign notes for example: “In Malawi, where malaria is the leading case of illness and death, up to 40 percent of women pregnant for the first and second time have placental malaria at the time of delivery, resulting in increased incidence of low birth weight and higher mortality for newborns and infants.”

DDT and Wildlife Impacts

The debate about whether DDT had a serious impact on wildlife is less clear. There is some evidence that widespread DDT use in the environment appears to have affected the ability of some birds of prey to reproduce, according to some sources. However, others claim that such problems were either overblown or that they are unfounded. In either case, the concern about DDT’s impacts on wildlife not related to public health uses of DDT that involve limited application to homes rather than environmental applications. As noted, residential uses of DDT can greatly help break the malaria transmission cycle without application in the environment and without adverse impacts on wildlife.