Carbon-black (1333864) and its environmental aspects are discussed. The properties and uses of carbon-black are considered. Carbon- black is the darkest substance known and is the most finely divided commercial substance, several orders of magnitude finer than the particulates that make up tobacco smoke. Its main commercial use is to reinforce elastomers and plastics. Approximately 94 percent of the carbon-black used in the United States is used in the rubber industry. Carbon blacks are classified according to their method of manufacture. Channel blacks are made by impingement of under ventilated natural gas flames, thermal blacks by thermal decomposition of natural gas, gas furnace blacks by partial combustion of natural gas, and oil furnace blacks by partial combustion of liquid hydrocarbons. Carbon-black and occupational safety are discussed. Carbon-black does not meet the OSHA criterion of a hazardous material. Although carbon-black has appeared on the NIOSH list of toxic substances, this was the result of an error. Potential toxic impurities in carbon-black are discussed. Carbon- black does not contain any detectable amounts of polychlorinated biphenyls. Analyses of typical rubber grade blacks have shown extremely small amounts, on the order of a few parts per million, of phenols, cyanides, and heavy metals. The extractable matter in carbon-black has been shown to contain polynuclear aromatic (PNA) compounds. Laboratory tests have shown, however, that the PNA are either not released at all or released so slowly that they are ineffective as carcinogens. The author concludes that there is no evidence of a health hazard due to carbon-black; however, extensive efforts have been made and are continuing to aid in ecological and environmental containment of the material.