This paper investigates the correlates of inequity in the distribution of exposure to air pollution in the state of Ohio. Although virtually all studies in the environmental justice literature analyze cross-sectional data, we construct a panel data set and estimate an econometric model of exposure utilizing the generalized method of moments. In addition, we postulate a surrogate for class position derived from data on estate tax collections. Even after accounting for some of the criticisms of the environmental justice literature, class and race are still significant correlates of the distribution of environmental burdens.