New EPA air toxics report presents sobering assessment of cancer risk

A new U.S. EPA report released today presents a scary picture of our exposure to hazardous pollutants in our air.  The National-Scale Air Toxics Assessment for 2002, which analyzed health data based on chronic exposure to air toxics for 124 pollutants for which those data are available.  (The assessment’s name is potentially confusing; the report analyzed data from 2002.)   The most important take-home message: over 2 million Americans live in census tracts where exposure to air toxics causes an increase of more than 100 in 1 million (or 1 in 10,000) in lifetime cancer risk.

Air toxics, unlike “criteria” air pollutants such as ground-level ozone and oxides of nitrogen whose main health impact is their contribution to smog, are more localized in their impact.  These substances can contribute to risk of cancer, respiratory illness, and other harms when inhaled.  Their unequal distribution across the country and even within communities has often not been remedied successfully even as the Clean Air Act has been relatively successful at cleaning criteria pollutants from the air.

The study was designed to answer these questions:

  • Which air toxics pose the greatest potential risk of cancer or adverse noncancer effects across the entire United States?
  • Which air toxics pose the greatest potential risk of cancer or adverse noncancer effects in some areas of the United States?
  • Which air toxics pose lesser, but still significant, potential risk of cancer or adverse noncancer effects across the entire United States?
  • When risks from all air toxics are combined, how many people have the potential for an upper-bound lifetime cancer risk greater than 10 in a million?
  • When potential adverse respiratory or neurological effects from all air toxics are combined, how many people have the potential for exposures that exceed reference levels intended to protect against adverse effects (i.e., a target organ-specific hazard index greater than 1.0)?
  • The study provides a wealth of information.  The bottom line for cancer risk:
    More than 284 million people live in census tracts where the combined upper bound lifetime cancer risk from these compounds exceeded 10 in one million risk and more than 2 million people live in census tracts where the combined upper bound lifetime cancer risk from these compounds exceeded 100 in one million risk. The overall national average risk in the U.S. is 36 in a million.
    For non-cancer risk, the agency created a “hazard index,” and found that for respiratory impacts, “the hazard index was dominated by a single substance, acrolein” and that the index indicated some impact (index of 1 or more) from air toxics for nearly the entire U.S. population, with a more serious impact (hazard index more than 10) for 22 million people.
    Los Angeles County, unsuprisingly, didn’t fare well.  Overall, these numbers are quite high, especially since they cover only outside inhalation risks from a particular set of air toxics.  Together with other cancer- and other disease-causing agents, the overall cancer burden placed on some communities by industrial and vehicular pollution is very high.
    The county-by-county assessment on the EPA’s maps provides only limited information about the localized impacts of these pollutants on particular communities.  But I expect that this dataset, with information by census tract, will be valuable for helping to gauge air toxic impacts on a smaller scale in the future, and, I hope, to motivate more governmental action to protect communities against air toxics.  I haven’t looked at the data, but I would be surprised if poor and minority communities aren’t hardest-hit.

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    Reader Comments

    8 Replies to “New EPA air toxics report presents sobering assessment of cancer risk”

    1. The report from the EPA on air toxics should not be taken seriously because the EPA has a record of poor scientific analysis which it uses to frighten and intimidate the public about environmental risks.

      The EPA has published false and inaccurate information about risks associated with climate change and this has undermined its credibility. As a result of the EPA’s perfidy, there are not enough votes in the House of Representatives to pass cap & trade legislation.

      It is unlikely that Congress will pass any environmental legislation this year.

      http://politicalticker.blogs.cnn.com/2009/06/24/house-democrats-unsure-of-global-warming-bills-passage/

    2. Jim,
      Thanks for your comments – I appreciate having regular readers who engage with the blog. But I’m not sure what your comment here about climate change (with similar content to comments you’ve left on 3 or 4 other recent posts) has to do with EPA’s analysis of this very different phenomenon. If you have some specific commentary about EPA’s methodology for the NATA 2002 study, that would be constructive and relevant here.

    3. Sean,
      I do not have specific commentary about EPA’s methodology for the NATA 2002 study.

      My comments above are personal reflections that are based on 28 years of experience as an Environmental Engineer, and during this time I have observed the EPA regulate, promulgate, litigate, investigate, and issue many reports and methodolgies.

      However, I understand that my comments were off-topic and in the future I will try to limit my comments to the topic of discussion.

    4. The results would be even worse if EPA had accounted for the cancer risk from diesel particulate matter. The South Coast Air Quality Management Board did just that in its MATES III study and found elevated cancer risk of greater than 3,600 in a million in the areas near the L.A. ports. This is a problem that is solveable with today’s technology, but industry has been fighting the necessary changes in court.

    5. David,
      In the year 2000 (which was an election year) the EPA released a report which said there were 438 deaths per year from air pollution in Houston.

      I was a member of an organization who investigated the EPA’s claim and we could not find any clinical evidence, death certificates, medical records, physician testimony, news reports, or other such data to substantiate that even one death occurred from air pollution.

      When confronted with our findings, the EPA said that it was using “premature deaths” which are based on weak statistical associations and not “actual deaths.”

      This is why I would not trust EPA’s health effects findings regarding elevated cancer risks. It is likely that elevated cancer risks reported by EPA are merely statistical manipulations and not actual cases of cancer that were definitely caused by inhaling diesel particulate matter.

      The research practices and procedures that are utilized by academics and clinicians in the medical profession are far superior and yield more reliable scientific data than EPA’s health effects studies.

    6. It would only make sense that poorer people would be harder hit, because housing is typically cheaper near industrial zones and high vehicular traffic areas, where the concentrations of air toxics are probably higher.

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    About Sean

    Sean Hecht

    Sean B. Hecht is the Co-Executive Director of the Emmett Institute on Climate Change and the Environment, Evan Frankel Professor of Policy and Practice, and Co-Director o…

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