Endocrine disruptors and testis development.

After serving on a panel convened by the U.S. EPA on epidemiological studies needed for evaluation of possible health risks of MTBE as a fuel additive, I feel that the article is quite informative and will no doubt be useful for those contemplating further use of oxygenated fuels. There are two matters that I feel are of some importance , and about them the article is silent. First, the report of symptoms from use in Fairbanks, Alaska, which stimulated much interest and concern, was associated with two unusual circumstances. First, because of the extreme cold weather, vehicle use is aberrant during the winter in Fairbanks; for example, car motors are left running once they are started. Secondly, the price of fuel increased sharply with the introduction of MTBE, so the public had to realize that there was a change. The second matter was made clear to the panel, but not widely disseminated. It consisted of the protection provided to drivers and service station attendants by the proper use of approved vapor recovery systems during the filling of gasoline tanks. Because such systems also prevent exposures to other fuel ingredients, which may include a certain amount of benzene, for example, they have an added value in health protection from whatever hazards exposure to gasoline may produce. In addition , they also prevent the emission of hydrocarbons, which can be involved in photochemical pollution. Your illustration of filling a gas tank without an approved vapor recovery system is most inappropriate. The article's discussion of cancer risk also omits the reference to the protection such systems may provide. I have advised the EPA that the universal requirement of such vapor recovery systems would have several other benefits to health and the environment, as well as obviating much of the need for further epidemiological studies of cancer risks from MTBE. There is broad experience with such systems, and there are abundant measurements to support this position. Endocrine Disruptors and Testis Development There is currently much debate as to which in vivo tests should be selected for the detection of adverse effects of endocrine disruptors in test animals. As coauthors of a much-cited article in Environmental Health Perspectives (1), which described small (but significant) decreases in testicular weight of adult rats that had been exposed developmentally to either of two environmental estrogens, we would like to bring certain of our experiences to the attention of …