The National Academies' planned peer review of the National Toxicology Program's (NTP) listings of formaldehyde and styrene in the 12th Report on Carcinogens (RoC) will look beyond the individual listings and also consider whether NTP's listing criteria produce sound results, rejecting the agency's attempts to limit the review's scope.
The peer review, as a result, calls into question the future of the process by which a chemical becomes listed in the RoC, a program that provides hazard information on carcinogenesis that EPA and other government agencies use to support policy decisions. The broader scope represents a victory for industry, which has criticized not only the individual RoC listings as scientifically flawed and procedurally nontransparent, but also the criteria that NTP has used to determine the listings. It also serves as a setback for the Department of Health and Human Services (HHS), which had asked the National Academies to examine the RoC only in the context of the current listing criteria.
The Academies' National Research Council (NRC) on Jan. 11 posted project scope information to its website, revealing some details on what the expert panels picked by the body will examine in the congressionally requested peer reviews. The website also includes lists of the chosen experts -- tentative selections, as NRC is taking comment on the panel selections for 20 days. Academic scientists comprise most of the "provisional committee appointments."
The NRC panels will search for and evaluate the publicly available, peer-reviewed literature, document how it includes or excludes studies from the evaluation and identify the most critical information, the website says. The panels will then apply NTP's listing criteria to the studies and make weight-of-evidence determinations for human and animal studies, integrate those conclusions and come up with listing recommendations for the chemicals, the website says.
"The committee will also comment upon the extent to which the listing criteria are likely to lead to scientifically sound listing recommendations," according to NRC's website.
HHS and the National Academies tussled over the reviews' scope last summer. In correspondence obtained by Risk Policy Report, the Academies said that HHS sought to exclude review of NTP's listing criteria from the scope -- which industry has criticized as lacking transparency and not applying a sufficient weight-of-evidence approach. The Academies responded in that letter that it viewed such a request as inconsistent with the 2011 congressional report language that requested the peer review (Risk Policy Report, July 24).
"Obviously, such reviews will necessarily evaluate the criteria used in the RoC as well as the published literature and other evidence," the Academies told HHS in a letter. "Congress did not allow that the Academy should accept the 'established RoC listing criteria' as a basis for its reviews."
The description of project scope posted Jan. 11 states the peer reviews will evaluate the individual listings with established RoC criteria but will also evaluate the criteria to determine their scientific soundness.
ACC in a Jan. 11 statement says that it "encourages the NAS effort to evaluate the current RoC's listing criteria to determine if it leads to scientifically sound recommendations. This is particularly important to ensuring that all relevant information is incorporated into future listing determinations."
The reviews are expected to have widespread attention, given the strong industry opposition to the listings and criticisms of the general RoC process. Government agencies also rely on the RoC to support policy decisions; for instance, EPA in 2010 reinstated a requirement for facilities to submit, as part of their Toxics Release Inventory reports, data on chemicals listed in the RoC.
NTP and HHS have strongly defended the RoC. NTP Director Linda Birnbaum has said that the program considers studies that both support and do not support a carcinogenesis finding; that the public has several opportunities to comment during the RoC process; that NTP has been fulfilling its congressional mandate; and that a panel of experts weighs in on the listing.
Still, congressional Republicans have taken note of industry criticisms and are weighing small-business advocates' recent calls to eliminate the RoC unless their demands for reform are met (Risk Policy Report, May 1). Democrats have characterized Republicans' oversight efforts as biased toward industry concerns.
The styrene industry has argued that NTP was not justified in listing the substance as "reasonably anticipated to be a carcinogen," and the Styrene Information and Research Center (SIRC) is challenging the listing in court. HHS and SIRC are seeking their own summary judgments in their favor (Risk Policy Report, July 17).
In comments filed with NTP as the program was putting together the 12th RoC, industry consultants with the firm Gradient criticized the styrene "reasonably anticipated" listing. Gradient scientists Lorenz Rhomberg and Julie Goodman put together their own weight-of-evidence analysis and data review and concluded that the listing was unjustified.
The Gradient consultants, with SIRC funding, also sought to have those findings published in the peer-reviewed literature, a styrene industry source says. After what the source calls an unexpectedly long wait, the study was published online in the peer-reviewed journal Human and Ecological Risk Assessment Jan. 2.
"As a whole, the evidence does not support the characterization of styrene as 'reasonably anticipated to be a human carcinogen,' and styrene should not be listed in the Report on Carcinogens," the paper says.
The paper was originally meant to provide an independent viewpoint on styrene's cancer-causing potential, the styrene industry source says -- the review was done before it was known that NRC would peer-review the styrene RoC listing. Now the paper also could influence the NRC peer review, says the source, who adds that the timing of its publication was purely coincidental.
Although the paper came out well after the June 2011 release of the 12th RoC, the Academies' website does not rule out that possibility that it could be considered, saying only that the panel will place "particular emphasis" on literature published before the RoC's release.
NTP, however, strongly rejected the claims in the consultants' public comments that underpin the paper's arguments -- suggesting that they face an uphill battle to gaining NTP acceptance. A spokeswoman for the National Institute of Environmental Health Sciences, where NTP is housed, did not respond to a request for comment.
Industry has similarly criticized the formaldehyde listing as a "known carcinogen." The American Chemistry Council (ACC) in its own litigation is suing HHS for certain documents that could shed light on how the department might have used a worker-exposure study to classify formaldehyde as a "known carcinogen."
ACC claims that HHS has failed to comply with a Freedom of Information Act (FOIA) request for the documents, but HHS has responded that it has already handed over all the documents that it was obligated to provide. The requested documents concern an occupational-exposure study of Chinese workers -- known as the Zhang study -- that linked formaldehyde exposures with increased risk of certain forms of leukemia.
EPA used the same study its draft Integrated Risk Information System assessment that found formaldehyde to be a leukemogen, a finding that an NRC panel that reviewed the report strongly criticized as unsupported by the evidence in April 2011. Industry is especially concerned about the leukemia links in the draft because such a finding would justify stricter regulation than would deeming formaldehyde to cause far rarer nasopharyngeal and sinonasal cancers, an idea that draws support from a wide range of human epidemiological and animal-based mechanistic studies.
ACC has asked the court for a speedy ruling on the FOIA matter. HHS has asked the court to dismiss the case outright "for lack of subject matter jurisdiction and [ACC's] failure to state a claim upon which relief can be granted" (Risk Policy Report, Nov. 13).
Now, with the NRC panel set to review the 12th RoC's formaldehyde monograph, ACC is offering its suggestions on how the group hopes the reviewers will approach their task.
"We support a robust review of formaldehyde that evaluates all the relevant scientific information, including information relating to: potential modes of action, human relevance, and responses at environmentally relevant exposures, to make an independent weight of evidence determination," ACC says in the statement. -- Puneet Kollipara