Samples of blood, sweat and urine were collected from eight control subjects and 19 lead workers in a battery manufacturing factory in the tropics. Sweat samples were collected while workers cycled on a bicycle ergometer at room temperature (27-31-degrees-C). All samples were analysed by atomic absorption spectrophotometry. Workers with blood lead levels of 13-36-mu-g dl-1 had sweat levels of 72-256-mu-g l-1 and urinary levels of 28-288-mu-g/g creatinine, while controls had levels of 9-12.2-mu-g dl-1, 9-30-mu-g l-1 and 9-19.6-mu-g/g creatinine, respectively. Estimations of sweat lead workers can be masked by skin contamination.