In a recent paper on the health impact of nuclear energy, 1 Katz stated that the ''nuclear establishment and international health authorities. .. play dirty tricks'' by a supposed concealment of information on the medical consequences of the Chernobyl disaster. The article 2 was discussed under the heading ''.. . dirty tricks,'' 1 although no particular tricks were specified. This letter does point out questionable methods (''tricks'') that lead to an overestimation of the consequences of the Chernobyl nuclear accident. In this author's opinion, Katz's article does require a critical comment. The main problem of the article is that it makes a lot of claims without providing evidence. For example, the following is stated as a separate paragraph without references: ''In Ukraine, Belarus, the Russian Federation, and many other countries contaminated to varying degrees by radionuclides from Chernobyl, there has been a significant increase in all types of cancer; diseases of the respiratory, cardiovascular, gastrointestinal, urogenital, endocrine, immune, lymphoid, and nervous systems; prenatal, perinatal, infant, and child mortality; spontaneous abortion, deformities, and genetic anomalies; disturbance and retardation of mental development; neuropsychological illness; and blindness.'' 1 Katz referred to the report published as Volume 1,181 of the Annals of the New York Academy of Science (hereafter referred to as ''NYAS Report''), 3 where it was suggested that the health consequences of the Chernobyl accident are far more serious than acknowledged by the nuclear establishment. According to Katz, the NYAS Report had been misrepresented-for example, in Jargin, 2 where it was demonstrated that a major