The Environmental Protection Agency is moving too quickly, and without sufficient information, on a scientific review that could pave the way for stricter standards on Hexavalent Chromium exposure, chemical manufacturers say.
EPA announced Sept. 30 that it was conducting a peer review of the scientific basis supporting the human health hazard and dose-response assessment of Hexavalent Chromium.
The final assessment will appear on the Integrated Risk Information System (IRIS) database, a human health assessment program that evaluates risk information on the effects of exposure to environmental contaminants. The IRIS assessments are used to support EPA’s regulatory activities. The database currently contains information for more than 540 chemical substances.
Hexavalent Chromium, also known as Cr(VI), is a carcinogenic compound used widely in primers, paints, and protective and decorative coatings.
The EPA’s decision to re-evaluate the compound follows a recent series of actions by the Occupational Safety and Health Administration to tighten standards on Cr(VI) inspection and exposure in the workplace.
Chemistry Council Criticism
The American Chemistry Council has urged EPA to delay the review, however, saying the agency knows that research now underway will provide more information on the compound.
The Council is a lobbying organization that represents dozens of chemical manufacturers, including AkzoNobel Chemicals, BASF Corp., Cognis Corp., LANXESS Corp., Evonik Degussa Corp., Dow and other key players in the coatings industry.
“ACC supports a comprehensive risk assessment of Hexavalent Chromium to ensure that any health risk posed by exposure is assessed as accurately as possible and is based on the best available science,” ACC Senior Director Ann Mason said in a public comment on the review.
However, she added, EPA issued its draft assessment “after recently shortening the previously announced timetable, rather than waiting for additional data that the agency knows is being developed.”
ACC criticized EPA’s use of results from 2008 National Toxicology Program (NTP) studies in its draft—research that left essential “data gaps in the Cr(VI) mode(s) of action,” the Council said.
Although the 2008 studies “included some significant new findings,” these were limited to rodents’ intake of high concentrations of Cr(VI) in their drinking water—exposure levels that “far exceeded” typical human exposures, the Council said.
To address those issues, ACC commissioned Toxicology Excellence for Risk Assessment (TERA), an independent scientific organization, to conduct its own review of the data. Those findings, to be released by early 2011, “could provide a more robust scientific basis to the cancer risk assessment,” Mason said.
She added: “It is unclear why EPA feels it necessary to act now, rather than wait to review the Cr(VI) studies underway, some of which have already been released for peer review. These studies are needed to provide EPA with additional important data and ‘the best available peer-reviewed science’ on any potential effects of Cr(VI) on human health.”
Applications and Review
Cr(VI) is used in the production of chromate pigments in dyes, paints, inks, and plastics; chromates added as anticorrosive agents to paints, primers, and other surface coatings; and chromic acid electroplated onto metal parts to provide a decorative or protective coating.
The compound can also be formed when performing "hot work" such as welding on stainless steel or melting chromium metal. (In these situations, the chromium is not originally hexavalent, but the high temperatures involved in the process result in oxidation that converts the chromium to a hexavalent state.)
EPA’s draft risk assessment was prepared by the National Center for Environmental Assessment (NCEA) within the EPA Office of Research and Development (ORD). On Sept. 30, EPA released the external review draft for public review and comment and the interagency science consultation review draft with comments.
EPA also announced a public listening session to be held on Nov. 18. The public comment period ends Nov. 29.
After the public review and comment period, public listening session, and external peer review, the draft Toxicological Review will be revised and submitted for a final agency review and an EPA-led Interagency Science Discussion. The final assessment will be posted on the IRIS database.
EPA declined to comment specifically on ACC's statement but said it welcomed all public comments on the review.