Our environment is polluted with toxic compounds including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (Co-PCBs). We investigated the suitability of hair analysis for testing human exposure to toxic compounds. Hair analysis revealed that municipal solid-waste (MSW) incineration workers were exposed to PCDDs, PCDFs, and Co-PCBs at high levels. The total 2,3,7,8-TCDD toxic equivalent concentration in MSW incineration workers was 2.5 times higher than in the general population, thus indicating that the indoor environment of the incineration facility was more polluted than the general environment. There were also characteristic patterns of occurrence of these dioxin-like compounds in the hair of smokers from the general population. We confirmed that hair analysis is useful for evaluating human exposure to PCDDs, PCDFs, and Co-PCBs in the atmosphere.