Arsenic, lead, and cadmium absorption levels were determined in 1774 children 1-5 years old living in 19 USA towns with primary nonferrous metal smelters. Results were compared with data on 258 children of the same age in three communities without smelters. Increased systemic absorption of arsenic, as reflected by urine arsenic content, was noted in children near 10 of 11 copper smelters. Blood lead levels were also modestly elevated near two copper smelters. Near lead and zinc smelters, elevated levels of lead and cadmium in hair provided evidence of external exposure to these elements. Levels of lead in blood were not, however, elevated near any of three lead smelters and were elevated near only two of five zinc smelters. Blood cadmium levels were high near one lead and two zinc smelters. The apparent sources of exposure (except in one community with elevated levels of arsenic in drinking water) were air, soil, and dust contaminated by smelting operations. While the full biologic significance of these findings is not known exposure of children to toxic heavy metals emitted by smelters should be reduced to a minimum.