An overview is presented of environmental conditions in the copper smelters operating in the United States through 1973 with data collected from surveys of the eight primary smelters. Airborne concentrations are included for arsenic, lead, zinc, copper, cadmium, molybdenum, and sulfur dioxide. Concentrations determined in the urine of smelters are included for arsenic, lead, copper, and cadmium. Airborne concentrations of sulfur dioxide were relatively high and variable in all smelters whereas concentrations of lead, zinc, cadmium, and molybdenum were consistantly low. Airborne coppers concentrations were relatively high in certain areas but occurred mostly as a non-respirable dust. Urine concentrations were not significantly higher than normal for arsenic, lead, and cadmium. The pararosaniline method and the hydrogen peroxide method are described for determining sulfur dioxide in the atmosphere.