Incinerator workers are exposed to many toxic compounds, most notably heavy metals. We evaluated medical and exposure monitoring data of an actively employed cohort of Philadelphia incinerator workers following an Agency for Toxic Substances and Disease Registry site survey and National Institute for Occupational Safety and Health (NIOSH) health hazard evaluation (HHE). Of the many airborne samples taken by NIOSH, only four of the personal breathing zone samples were above OSHA or ACGIH standards: one for lead, one for phosphorous, and two for total particulates. Because samples were taken during limited operations (only one of the two incinerators were operating), the results may underestimate historical exposures at this site. We limited our medical analysis to the 86 male workers who participated in the HHE out of the 105 active employees. The 86 employees were divided into potential high and low exposure groups based on a work site analysis done by an independent industrial hygienist. Eight individuals had at least one elevated biological index indicating exposure to a heavy metal. These elevations, however, were unrelated to the workers' exposure categories. Furthermore, no clinically significant mean blood or serum measurements were noted. Thirty-four percent of the workers had evidence of hypertension which increased the risk of significant proteinuria. Neither hypertension nor proteinuria were related to exposure group. Changes in pulmonary function related only to smoking status. Although there was some evidence of an increased risk of exposure to products of incinerator waste, we could not relate the few elevated biological tests to exposure classification. Additional studies are needed to assess the potential health effects of municipal waste incinerator by-products.