In order to evaluate the stability of benzo[a]pyrene diolepoxide--DNA adducts two separate studies were carried out in rats, either treated i.p. with benzo[a]pyrene (100 mg/kg body wt) or sham-exposed. The measurement of DNA adducts in 155 samples of liver, lung or heart, each of them tested in duplicate, was performed by synchronous fluorescence spectrophotometry. In the first study fragments of rat liver or lung were stored for varying times at varying temperatures. No decrease of adduct levels occurred at 4 degrees C for at least 72 h, whereas a significant decrease was recorded in both liver and lung after 48 h at 20 degrees C or 24 h at 37 degrees C. In the second study liver, lungs and heart were collected from rats either immediately after killing or after storage of cadavers for 16 h at 20 degrees C or 16 h at 20 degrees C plus 24 h at 4 degrees C, thereby mimicking typical storage conditions of human cadavers before autopsy. Under these conditions no significant variation of fluorescent adducts was observed in any organ. In conclusion, at least for this kind of adduct, the use of autopsy samples following proper storage of cadavers seems to be acceptable.