Metallurgical processes, such as smelting. can generate organic impurities such as organic chloride chemicals, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). The objective of this study was to elucidate the serum PCDD/F levels of 134 workers and ambient air levels around electric arc furnaces (EAF), secondary copper smelters and secondary aluminum smelters (ALSs) in Taiwan. The highest serum PCDD/F levels were found in the ALSs workers (21.9 pg WHO-TEQ/g lipid). with lower levels in copper smelter workers (21.5 pg WHO-TEQ/g lipid), and the lowest in the EAF plant workers (18.8 pg WHO-TEQ/g lipid). This was still higher than the levels for residents living within 5km of municipal waste incinerators (14.0 pg WHO-TEQ/g lipid). For ambient samples, the highest ambient air PCDD/F level was in the copper smelters (12.4 pg WHO-TEQ/Nm(3)), with lower levels in ALSs (7.2 pg WHO-TEQ/Nm(3)), and the lowest in the EAF industry (1.8 pg WHO-TEQ/Nm(3)). The congener profiles were consistent in serum and in air samples collected in the copper smelters, but not for ALSs and EAR In secondary copper smelters, the air PCDD/Fs levels might be directly linked to the PCDD/Fs accumulated in the workers due to the exceedingly stable congener pattern of the PCDD/F emission. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.