Styrene oxide, a metabolite of styrene, reacts with many centres in nucleosides but in DNA N-7-, N2- and O6-guanine are the main sites. A 32P-postlabelling method was developed for the detection of O6-styrene oxide DNA adducts from white blood cells. The method involved use of nuclease P1 and magnet transfer. The O6 adducts were detected at a fmol range with about 10% labelling efficiency. In lamination workers the O6 adducts, adjusted for adduct recovery, were detected at a level of 5 adducts/10(8) nucleotides.