(1) Orchardists who died of other causes during this period served as controls.
(2) Urine samples were obtained during pre-spraying and spraying periods from 22 non-smoking orchardists who spray large amounts of pesticides during the fruit growing season.
(3) However, clastogenic activity of urine specimens collected during the spraying period was significantly elevated (p less than 0.001) for the highly-exposed orchardists, but not for the research station personnel.
(4) Cases included all white male orchardists who died in Washington State between 1968 and 1980 from respiratory cancer.
(5) Clastogenicity of orchardists' urine was observed within 8 h of pesticide application.
(6) Genotoxicity in the urine of orchardists occupationally exposed to pesticides was investigated.
(7) Although cigarette smoking was unusually common among cases of respiratory cancer, smoking habits of the orchardists and a sample of non-orchardists who had died of other causes were quite similar.
(8) This paper will correlate data from a number of studies in which the dermal penetration of azinphosmethyl (AM) was measured in rats, rabbits, monkeys and man; and urinary alkyl phosphate metabolites were measured in orchardists exposed to AM.
(9) The cause of the excess mortality from respiratory cancer among Washington State orchardists remains unknown.