I would like to reply to the editor’s response [v28 i15] to my recent letter about PFAS and elaborate somewhat on PFAS.My letter relied mostly on findings published by the Agency for Toxic Substances and Disease Registry (ATSDR). The editor’s response invoked a 2009 report on the ATSDR issued by the House of Representatives’ subcommittee report. I was not aware of any of this, and in the future I will not use ATSDR material.Although Congress authorized the ATSDR in 1980, the agency did not emerge until 1983. According to the introduction to the Subcommittee Report, the ATSDR “had an extremely difficult birth and has struggled ever since.” The ATSDR was never able to fill all its staffing positions, and the EPA and the Office of Management and Budget Services (HHS) never wanted ATSDR to have its own staff, and the report said, “The EPA and HHS provided it with little support and at times tried to subvert it.” I am not trying to defend ATSDR. Based on my reading of portions of the subcommittee report, I must say that the agency has some serious moral and ethical shortcomings and much of its behavior has been dishonest and underhanded.Leaving the ATSDR behind, what does the EPA have to say about PFAS and related chemicals? According to its website, studies “indicate” that some of the related chemicals “can cause reproductive and developmental, liver and kidney, and immunological effects in laboratory animals.” These laboratory animals were exposed to much higher doses than are humans. Some of these results have not been repeated in other studies, and whether animal studies can be applied to humans is a matter of debate.According to a 2007 review paper, “In general, no consistent association between [PFAS and related chemicals] and adverse health effects has been observed.” (The studies were conducted on workers who had received occupational exposure.) The studies are small studies, few cases of cancer have been observed or the studies lack adequate exposure data. Some studies that show increased cancer mortality do not reach statistical significance, meaning the increase could be due to chance and not to exposure. A January 2019 review paper on PFAS was full of qualifiers: “Results should be interpreted with caution until they could be replicated;” “whether [an] association had any public health significance was debatable;” “associations were either likely due to chance, or study size was too small, or no meaningful associations were found.”To briefly address what is probably the biggest worry of all—cancer—I will reiterate what I said in my April 4 letter. Seventy-eight percent of cancer is caused by smoking, diet, prolonged excessive drinking (especially of hard liquor), certain sexual practices, obesity and inadequate exercise. That is, 78 percent of cancer is caused by human behavior. By themselves, smoking and diet cause about 65 percent of cancer.Every year in the United States, 450,000 people die as a direct result of smoking cigarettes. Although not all of these are cancer deaths, according to the American Lung Association, 90 percent of lung cancer is caused by smoking. If you smoke and you are worried about cancer, stop smoking! If you don’t smoke, don’t start, and follow the rest of the advice in the preceding paragraph.
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