Pollution and Acquisition: the Environmental Justice Effects of Mergers
Abstract
I estimate the effect of mergers and acquisitions on both facility-level high-risk air pollution, and also the distribution of toxic air pollution within firms as the number and geographic distribution of their held facilities changes. This work improves our understanding of the supply-side of neighborhood-level pollution, which has been widely shown to threaten long-term health and cognition, particularly for vulnerable populations.Even though the majority of Toxics Release Inventory facilities—the major contributors of harmful point-source industrial emissions at scale in the U.S.—are owned by parent companies who control at least ten, and sometimes hundreds of separate plants, we know relatively little about the role of firm decisions in the allocation of high-risk air pollution across plants.
The effect of a merger on facility emissions is not obvious: acquiring companies tend to be larger and better-resourced, and may implement more efficient pollution control; on the other hand, a merger may enable firms to reduce risky emissions in more advantaged communities, where the expectation of regulation is higher. Since acquisition is endogenous to the operation and emissions of an event study design that allows for treatment effect heterogeneity.
Over the study period from 2001–2018, I find emissions fall substantially at target facilities after an acquisition, and many close down entirely. Reductions are consistent with parent companies reducing activity and improving pollution-control practices. However, with a larger set of facilities available to polluting firms, I also find evidence of a redistribution of pollution within parent companies to facilities in more-disadvantaged neighborhoods. This result suggests consolidation in polluting sectors may enhance environmental inequality, and raises the question of whether regulators should consider the distributional effects of mergers in heavily polluting industries.