An evaluation of lead (7439921) contamination in an office building complex was performed in response to employee complaints about particulate fallout from heating, ventilation, and air conditioning (HVAC) ductwork in offices of the North Carolina Department of Transportation (NCDOT), Raleigh. The NCDOT offices were housed in a complex of three connected buildings: the Highway, Annex, and Museum Buildings. The Highway and Annex Buildings which shared the same HVAC system were evaluated. The evaluation consisted of several surveys conducted from January through August 1992. Black particulate matter ranging in size from less than 1 to 5 millimeters (mm) was found in most areas of the Highway Building and in some areas of the Annex Building. Similar accumulations were found in the ductwork. One sample found on a window sill of the Highway Building contained 7,231 micrograms (microg) per square meter (m2) lead. Settled dust samples found on the floors and work surfaces contained 0 to 6,607microg/m2 lead. Lead concentrations in particulate accumulations in the ductwork ranged from 764 to 1,653,812microg/m2. No airborne lead was detected. In the Annex Building, lead concentrations of 7,661 to 13,235microg/m2 were measured in the ductwork. Lead concentrations on the floors and work surfaces ranged from nondetectable to 1,173microg/m2. Airborne lead concentrations up to 5.3microg per cubic meter were detected. Blood lead concentrations were measured in 130 workers in August 1992. None were elevated above the action level for women of childbearing age, 10microg per deciliter (dl). Blood lead concentrations in the Highway and Annex Building workers ranged from 0 to 5 and 0 to 7microg/dl, respectively. After the HVAC ducts were cleaned, additional environmental sampling for lead was conducted. Lead concentrations in the ductwork and on surfaces outside the ductwork in the Highway Building ranged from 1,560 to 194,218 and from nondetectable to 581microg/m2, respectively. The authors conclude that the NCDOT buildings were contaminated with lead containing dusts that were disseminated throughout the buildings by the HVAC system. The amount of lead detected on working surfaces was not a good indicator of employee intake when assessed by blood lead concentrations. These findings suggest that the risk of lead toxicity for employees working in buildings where similar lead concentrations exist may be minimal.