IRIS Update: EPA Announces New Program to Revise Old Chemical Profiles

by Matt Shudtz

October 22, 2009

In Wednesday's Federal Register, EPA unveiled a new, streamlined process through which agency scientists will systematically review old chemical profiles in the IRIS database and update them with the latest toxicological information. With everything from Clean Air Act residual risk determinations about hazardous air pollutants to Superfund site cleanup standards to Safe Drinking Water Act regulations turning on the toxicological profiles housed in the IRIS database, it is a huge step in the right direction for EPA to be proactively screening old profiles to make sure they are up-to-date.

In 2003, the Eastern Research Group conducted a literature review to determine which chemicals in the IRIS database had been the subject of new toxicity or carcinogenicity studies since their last significant IRIS update. The researchers identified new health effects information for 169 chemicals (37% of those reviewed) that, if evaluated in detail, could possibly result in a change to an existing value. Additionally, the researchers found studies that could possibly fill data gaps for 281 chemicals (61% of those reviewed) whose IRIS entries were incomplete. Only a handful of chemical profiles made it through the Bush Administration’s IRIS assessment process, so it is unlikely the numbers have changed much since the Eastern Research Group’s study was published.

The IRIS Update Project, as described in Wednesday’s Federal Register notice, will focus on revising toxicological profiles that are more than 10 years old and will prioritize those chemicals that are most important for Clean Air, Superfund, and Clean Water program staff. The seven-step process that EPA has laid out seems reasonable enough, although the announcement is a bit thin on details for a majority of the seven steps. Here is how EPA describes the process:

  1. Publish an annual Federal Register notice announcing EPA’s IRIS Update Project agenda and calling for scientific information from the public regarding assessments on the agenda;
  2. Conduct a comprehensive search of the current scientific literature on each assessment;
  3. Develop draft health assessment documents using state of the science methods and guidelines;
  4. Conduct a combined simultaneous review of the draft assessment documents by EPA and other Federal Agencies via the Federal Standing Science Committee;
  5. Solicit public comments on draft assessments, followed by independent external peer review under the Federal Advisory Committee Act (FACA);
  6. Prepare final IRIS assessments that reflect public comments and independent expert review; and
  7. Replace the existing assessments with the final updated IRIS assessments on the IRIS website.

Wednesday’s announcement does not get into the details of Steps (3) through (7), and, of course, these are the aspects of the program that are most likely to lead to the heated debates that can derail an IRIS assessment. But it is good to see that EPA will be utilizing the FACA framework to engage external peer reviewers. FACA is not perfect, but it will provide a degree of transparency and protection from bias that will benefit the IRIS Update Program.

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