Research AreasEnvironmental and Energy EconomicsCorporate Toxics Information ProjectToxic 100 Air Polluters Index2013 Press Release

Toxic 100 Air Polluters Press Release


Contact Prof. Michael Ash or Prof. James K. Boyce +1-413-577-3147 or



AMHERST, MA, August 19, 2013 – Researchers at the Political Economy Research Institute (PERI) at the University of Massachusetts Amherst today released the Toxic 100 Air Polluters (, an updated list of the top corporate air polluters in the United States.

“The Toxic 100 Air Polluters informs consumers, shareholders, and communities which large corporations release the most toxic pollutants into our air,” said Professor James Boyce, co-director of PERI's Corporate Toxics Information Project. “We assess not just how many pounds of pollutants are released, but which are the most toxic and how many people are at risk. People have a right to know about toxic hazards to which they are exposed. Legislators need to understand the effects of pollution on their constituents.”

The Toxic 100 Air Polluters index is based on air releases of hundreds of distinct chemicals from tens of thousands of industrial facilities across the United States. The rankings take into account not only the quantity of releases, but also the toxicity of chemicals, transport factors such as prevailing winds and height of smokestacks, and the number of people exposed.

The top five air polluters among large corporations are Precision Castparts, DuPont, the Bayer Group, Dow Chemicals and ExxonMobil.* Since 2010 the Toxic 100 Air Polluters rankings has included large privately held firms, such as number fifteen Koch Industries, as well as the world’s largest publicly traded corporations.

The Toxic 100 Air Polluters also includes information on the disproportionate risk burden from industrial air toxics for minorities and low-income communities. This makes it possible to compare corporations and facilities in terms of their environmental justice performance as well as overall pollution. For example, the data reveal that minorities bear 74 percent of the air toxics risk from facilities owned by ExxonMobil (sixth among all polluters on the Toxic 100), while minorities make up less than 40 percent of the U.S. population.

Users of the web-based Toxic 100 Air Polluters list can view the details behind each company’s Toxic Score, including the names and locations of individual facilities owned by the corporation, the chemicals emitted by those facilities, and the share of the Toxic Score borne by minorities and people living below the poverty line. The web edition also provides a searchable database with this information for all firms operating in the United States, regardless of size.

The data on chemical releases come from the U.S. Environmental Protection Agency's Toxics Release Inventory (TRI). The TRI is widely cited in press accounts that identify the top polluters in various localities. But reports based on TRI data alone have three limitations:

  • Raw TRI data are reported in total pounds of chemicals, without taking into account differences in toxicity. Pound-for-pound, some chemicals are up to ten million times more hazardous than others.

  • TRI data do not consider the numbers of people affected by toxic releases--for example, the difference between facilities upwind from densely-populated urban areas and those located far from population centers.

  • TRI data are reported on a facility-by-facility basis, without combining plants owned by one corporation to get a picture of overall corporate performance.

The Toxic 100 index tackles all three problems by using the 2010 Risk-Screening Environmental Indicators (RSEI) data from the EPA. In addition to TRI data, EPA’s RSEI includes toxicity weights, fate-and-transport modeling, and population exposure to provide a comprehensive picture of chronic human health risk from airborne industrial toxics. PERI researchers add up facility-by-facility RSEI data published by the EPA to construct corporate rankings.

“In making this information available, we are building on the achievements of the right-to-know movement,” explains Professor Michael Ash, co-Director of the Corporate Toxics Information Project. “Our goal is to engender public participation in environmental decision-making, and to help residents translate the right to know into the right to clean air.”


For further information, contact Professor Michael Ash or Professor James K. Boyce at  +1-413-577-3147 or or visit PERI's Corporate Toxic Information Project on the web at

* September 3, 2013: Biomet, Inc., which the initial listing ranked at number three among the Toxic 100, has submitted data to the U.S. EPA revising its 2010 TRI reporting. Based on the revision, Biomet, Inc., is ranked 71st on the Toxic 100 with a RSEI Score of 208,173. The next edition of the Toxic 100 will reflect the most current information from the EPA.