This paper examines whether the impact of environmental regulations differs by the size of the business. We consider the net effect of statutory, enforcement, and compliance asymmetries by estimating the relationship between plant size and pollution abatement expenditures, using establishment-level data on U.S. manufacturers from the Census Bureau’s Pollution Abatement Costs and Expenditures (PACE) survey and from its Annual Survey of Manufactures and Census of Manufactures. We model establishments’ pollution abatement operating costs (PAOC) per unit of economic activity as a function of establishment size, industry, state, and year. Our results show that PAOC intensity increases with establishment and firm size.