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Weighing In On EPA Research

Science advisers to suggest improvements for work on computational toxicology, cost estimates of regulations

by Cheryl Hogue
March 4, 2013 | A version of this story appeared in Volume 91, Issue 9

Science Advice


EPA’s Science Advisory Board is providing recommendations on two areas of research related to the regulation of chemicals.

◾ Computational toxicology: The agency is working toward integrating information from high-throughput testing methods into its chemical risk assessments.

◾ Cost estimates for regulations: The agency is studying 10 rules that have been implemented to compare the predicted cost with the actual cost.

This week, scientific advisers to the Environmental Protection Agency are scheduled to finalize critiques of two agency research efforts that, in coming years, will likely influence the regulation of commercial chemicals and pesticides.

One review by the agency’s Science Advisory Board (SAB) focuses on EPA’s computational toxicology program, a research effort launched in 2007. This work melds chemistry, molecular biology, and computer science to scrutinize chemicals’ effects using high-throughput testing methods employed by the pharmaceutical industry. The agency intends eventually to use computational toxicology data in risk assessments of chemicals (C&EN, June 11, 2012, page 32).

The other SAB critique involves an EPA effort to make the agency’s cost estimates for pending regulations more accurate. Published studies show that these estimates tend to overstate actual costs more than they underestimate them (C&EN, May 7, 2012, page 26).

SAB is slated to finalize the reviews at a March 7–8 meeting in Washington, D.C.

In a draft version of its critique of EPA’s computational toxicology program, SAB commends the agency for diving into this evolving area of science. The draft notes, though, that the agency has not yet begun to apply this information to regulatory work such as prioritizing chemicals for further scrutiny, screening substances for potential adverse effects, or assessing the risks that compounds pose to human health or the environment. “The program has not had sufficient time to demonstrate that it can deliver on its promise,” the draft says.

Acceptance both within the agency and by the public for the use of computational toxicology in EPA’s regulatory decisions is likely to grow as this science matures, the draft states. EPA’s integration of computational toxicology data into its regulatory work is apt to begin by supplementing, then probably replacing, existing methods such as experiments with lab animals, it adds.

To ensure acceptance, scientists need to demonstrate that computational toxicology data are valuable in predicting a chemical’s hazard, showing that this information is sufficiently able to estimate toxicity in lab animals and, ultimately, in people. Only then will agency decisions relying only on computational toxicology data “be scientifically defensible within an acceptable level of uncertainty,” the draft says.

Much of the agency’s research on computational toxicology is focused on what are called adverse outcome pathways. These are the connections between an event at the molecular level, such as an interaction between a chemical and a nuclear hormone receptor, and adverse health effects. SAB’s draft review urges EPA to partner with research institutions and professional societies that have a mission to understand particular diseases. For example, EPA could work with the National Institutes of Health’s National Heart, Lung & Blood Institute or the American Lung Association as it explores the adverse outcome pathways for asthma, the draft points out.

The draft endorses EPA’s goal of putting all its computational toxicology data online for the public to view and interpret. “These data will likely be the source of numerous Ph.D. dissertations in the near future,” the draft says. But it adds that the agency needs to make its computational toxicology website,, easier to navigate.

The second draft critique is focused on a report EPA is preparing in response to a 2011 directive from President Barack Obama to ensure that the benefits of federal rules justify their costs. This EPA study involves 10 major environmental regulations dating back as far as the late 1990s to determine what factors caused inaccuracies in cost estimates that the agency prepared before the rules were issued.

The SAB draft endorses EPA’s effort to look back at cost estimates, saying that accurate assessment of the cost of rules before they are issued is critical to designing cost-effective regulations. Estimates that are too low can lead to regulations that are too stringent, it says, and those that are too high can lead to rules that are not protective enough of health or the environment.

The draft, however, urges the agency to do “a proper evaluation” that includes many more than the 10 rules EPA selected for the study. In addition, the agency needs to collect information about the costs of compliance with its rules once they are issued, using surveys, focus groups, expert groups, and outside researchers, the draft says. It notes that the agency does not typically gather this sort of after-the-fact data.

After the board completes its work on both drafts, the final reports will be sent to the EPA administrator for consideration.



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