US National Academy of Sciences to launch 'comprehensive examination' of chemical health assessments

The US Environmental Protection Agency's (EPA) controversial human health assessment programme will be reviewed by the US National Academy of Sciences (NAS). Specifically, the NAS will conduct a 'comprehensive examination' of the assessment process that underlies the EPA's Integrated Risk Information System (IRIS), through which the agency provides health data on over 550 chemical substances.

The IRIS review, announced on 16 May, will consider changes that the EPA is making in response to NAS's previous recommendations from April 2011 about the agency's IRIS assessment of the potential health effects of formaldehyde exposure. The EPA had concluded that the chemical is a human carcinogen.

In that April 2011 report, the NAS determined that the EPA's draft assessment of formaldehyde did not adequately support its conclusions that the compound causes certain cancers of the respiratory tract, leukemia or several other health problems. It also identified recurring problems with 'clarity' and 'transparency' with the EPA's chemical assessments in recent years. The NAS has warned that the agency's future assessments may suffer from the same weaknesses if these problems are not addressed.

As part of its review, the NAS will examine current methods for weighing evidence analyses and it will recommend approaches for gauging the scientific evidence for chemical hazard identification.

The American Chemistry Council (ACC) has applauded the NAS for investigating IRIS assessments. The trade group says news of the upcoming study makes it clear that 'more work is needed to get EPA's IRIS programme back on track' and ensure that the agency produces 'scientifically sound assessments that are capable of guiding public health decisions'.

Specifically, the ACC is encouraged by the fact that the upcoming review will suggest methods for weighing scientific evidence for both cancer and other health conditions, which it calls 'crucial' to strengthening the scientific foundation of IRIS.

The EPA also appears to be enthusiastic, welcoming the review. The agency said it is taking a 'phased approach' to adopting the NAS recommendations from April.

The ACC has voiced its concern with the EPA's approach in the past, arguing that the agency continues to fall short of making the needed improvements to ensure that IRIS delivers clear and objective assessments based on sound science. Until such changes are made, the group has said that the programme will continue to produce results that 'create unnecessary confusion and fail to properly guide public health decisions'.

Rebecca Trager