A recent report released by the National Academy of Sciences ("NAS") is critical of U.S. EPA's draft risk assessment for formaldehyde. U.S. EPA's draft assessment, which was released for comment in June 2010, had concluded that formaldehyde was a carcinogen and could cause lymphohematopoietic and nasal cancers. The draft risk assessment also included a strict (and fairly controversial) inhalation unit risk factor of 8.1×10-2 parts per million-1. If the draft assessment were to become final (at least in its current form), it would likely result in a myriad of stringent emission regulations on products such as plywood, carpet and natural gas turbines, all of which emit formaldehyde.
The NAS, however, was critical of the agency's finding, noting that U.S. EPA's "conclusions appear to be based on a subjective view of the overall data, and the absence of a causal framework for [lymphohematopoietic cancers] is particularly problematic given the inconsistencies in the epidemiologic data, the weak animal data, and the lack of mechanistic data. Although EPA provided an exhaustive description of the studies and speculated extensively on possible modes of action, the causal determinations are not supported by the narrative provided in the draft IRIS assessment." More specifically, the report questioned whether there was any linkage between formaldehyde exposure and leukemia or Hodgkin lymphoma, noting that there appeared to be a disconnect between the conclusions reached in the draft assessment and the studies that were evaluated. (The report did, however, acknowledge that there appears to be strong epidemiologic evidence of a link between formaldehyde exposure and certain nasal cancers.) The NAS report also recommended that U.S. EPA reevaluate its use of linear modeling of the cancer risk, an approach that assumes there is no safe level of exposure to formaldehyde and adopt a different approach for estimating formaldehyde's non-cancer risks.
In response to the NAS study, a U.S. EPA spokesperson said "we will carefully and expeditiously review the report, as we do with all peer review reports, and examine how best to respond to its recommendations."
The NAS report can be obtained from the National Academy of Sciences website.