The Political Economy Research Institute at the University of Massachusetts Amherst has published a report, the Toxic 100 Air Polluters Index, that one might be more inclined to expect from an environmental group. PERI, however, has done it better than most environmental groups and the North American Commission for Environmental Cooperation.

The Toxic 100 Air Polluters Index highlights the top U.S. air polluters among the world’s largest corporations. The underlying data are from the EPA’s Toxics Release Inventory, in which facilities across the U.S. report their releases of toxic chemicals. However, unlike many other lists of top polluters, which often simply add together the quantities of low toxicity and high toxicity pollutants,  the Toxic 100 also takes into account the degree of toxicity of the releases and the population exposed. This is a fairly sophisticated list.

Among the leaders are some household names:

• du Pont
• Bayer Group
• Dow Chemical
• ExxonMobil
• BASF
• General Electric

and hundreds more. Despite the name the list ranks all companies which report to the Toxics Release Inventory, not just the top 100.

PERI points out that there are quite a few potential sources of error in the data, almost all of them associated with poor reporting by the companies themselves. Potential sources of error include:

1. Incorrect data submitted by facilities.
2. Imprecise data submitted by facilities.
3. Inadequate information on stack heights.
4. Toxicity weights for chemical groups.
5. Lack of toxicity weights for some chemicals.
6. Geographical limits of modeled dispersion
7. Focus on long-term health effects.
8. Products of decay not modeled.
9. Imprecise location of facilities.
10. Releases assumed to be constant over time.
11. No reporting of emissions from mobile sources, such as trucks, automobiles, ships, and aircraft.
12. The chemicals in the TRI do not include some bulk pollutants that pose significant health and environmental risks, including sulfur dioxide, nitrogen oxides, ozone, carbon monoxide, particulate matter, and carbon dioxide.

These are the same kind of problems that dog other pollutant release and transfer registries, such as Canada’s National Pollutant Release Inventory. Why government and industry do not get together to fix the problems is very strange: it seems inconceivable that anyone wins by having inaccurate pollutant release data circulating in the public domain.

Another question might be why a political economy research institute at a respected university is publishing a Toxics 100 list. Apparently the folks at PERI are interested in environmental justice. They calculate environmental justice ratios using geographical microdata generated by the model behind Toxics 100, then match the grid cells to U.S. Bureau of the Census geography, and make links to data on race, ethnicity, and poverty.

It is one of many environmental lists, most of them fingering supposed ‘bad’ companies, about which those with operations in the US should be aware.

The Toxic 100 is fully available, with many explanatory texts, at http://www.peri.umass.edu/toxic100/