The relationship between economic activity and environmental pollution is a topic of extensive research. Although a proportional relationship between the two is often the default assumption, emerging scholarship suggests that polluting releases are disproportionally distributed across units of production. This paper examines if proportionality or disproportionality best characterizes the production of toxic pollution in US manufacturing from 1998 to 2012. Examining US Environmental Protection Agency Toxics Release Inventory data from over 25 000 facilities in 322 industries, we find consistently high levels of disproportionality across facility-level toxic releases within industries, even when controlling for facility size. Moreover, high levels of within industry disproportionality are remarkably stable over the fifteen-year study period. In other words, year by year a small handful of egregiously polluting facilities account for the vast majority of toxic releases within a given industry. Our findings suggest that disproportionality should be understood as the default pattern of pollution generation rather than an exceptional case and that policymakers should seek to reduce pollution via carefully considered targeting strategies rather than broad-stroke decision making.