E9-2823. National Toxicology Program (NTP); Report on Carcinogens (RoC); Request for Public Comments on the RoC Expert Panel's Recommendation on Listing Status for Cobalt-Tungsten Carbide Powders and Hard Metals in the 12th RoC and the Scientific ...

AGENCY:

National Institute of Environmental Health Sciences (NIEHS); National Institutes of Health (NIH).

ACTION:

Request for comments.

SUMMARY:

The NTP invites public comment on the recommendation from an expert panel on the listing status for cobalt-tungsten carbide powders and hard metals in the 12th RoC and the scientific justification for the recommendation. The recommendation and scientific justification for cobalt-tungsten carbide powders and hard metals are available electronically in Part B of the Expert Panel Report (http://ntp.niehs.nih.gov/​go/​29682,, see Expert Panel Report Part B) or in printed text from the RoC Center (see FOR FURTHER INFORMATION CONTACT below). The RoC Center convened a seven-member expert panel of scientists, plus one technical scientific expert, from the public and private sectors on December 9-10, 2008. The panel was asked (1) to apply the RoC listing criteria to the relevant scientific evidence and make a recommendation regarding listing status (i.e., known to be a human carcinogen, reasonably anticipated to be a human carcinogen, or not to list) for cobalt-tungsten carbide powders and hard metals in the 12th RoC and (2) to provide the scientific justification for the recommendation.

DATES:

The Expert Panel Report (Part B) for cobalt-tungsten carbide powders and hard metals will be available for public comment by February 4, 2009. Written comments should be submitted by March 30, 2009.

ADDRESSES:

Comments should be sent to Dr. Ruth Lunn, Director, RoC Center [NIEHS, P.O. Box 12233, MD K2-14, Research Triangle Park, NC 27709, FAX: [phone], or [e-mail]. Courier address: Report on Carcinogens Center, NIEHS, 530 Davis Drive, Room 2006, Durham, NC 27713].

FOR FURTHER INFORMATION CONTACT:

Dr. Ruth Lunn, RoC Center, 919-316-4637 or [e-mail].

SUPPLEMENTARY INFORMATION:

Background

Cobalt-tungsten carbide hard metals are composites of carbides (including tungsten carbide alone or in combination with small amounts of other carbides) with a metallic cobalt binder, pressed into a compact, solid form at high temperatures by a process known as “sintering.” Cobalt-tungsten carbide hard metals are used primarily in cutting tools. Cobalt-tungsten carbide hard metals are manufactured and used in the United States. Occupational exposure to cobalt-tungsten carbide hard-metal particles can occur during hard-metal production, recycling of hard-metal products, and grinding and sharpening of hard-metal tools.

As part of the RoC review process (available at http://ntp.niehs.nih.gov/​go/​29353), the NTP announced the availability of the draft background document for cobalt-tungsten carbide powders and hard metals (73FR60288), invited public comments on the draft background document, and announced the cobalt-tungsten carbide powders and hard metals expert panel meeting. The RoC Center convened a seven-member expert panel of scientists from the public and private sectors to evaluate cobalt-tungsten carbide powders and hard metals. An additional, non-voting, expert scientist was also in attendance to respond to technical concerns from the panel. The expert panel met on December 9-10, 2008, in a public forum at the Sheraton Chapel Hill Hotel, Chapel Hill, North Carolina. The panel was charged to peer review the draft background document for cobalt-tungsten carbide powders and hard metals and then to make a recommendation on its listing status in the 12th RoC and to provide a scientific justification for that recommendation. Details about the meeting, including public comments received and the expert panel reports, are available on the RoC Web site (http://ntp.niehs.nih.gov/​go/​29682). The expert panel report for cobalt-tungsten carbide powders and hard metals contains two parts: Part A has the peer-review comments on the draft background document and Part B has the recommendation on listing status and its scientific justification. The expert panel recommended that cobalt-tungsten carbide powders and hard metals be listed in the 12th RoC as reasonably anticipated to be a human carcinogen.

Request for Comments

The RoC Center invites written public comments on the expert panel's recommendation on listing status for cobalt-tungsten carbide powders and hard metals and the scientific justification for the recommendation. All comments received will be posted on the RoC Web site. Persons submitting written comments are asked to include their name and contact information (affiliation, mailing address, telephone and facsimile numbers, e-mail, and sponsoring organization, if any) and send them to Dr. Lunn (see ADDRESSES above). The deadline for submission of written comments is March 30, 2009.

Next Steps

The RoC Center is in the process of finalizing the background document for cobalt-tungsten carbide powders and hard metals based upon the expert panel's peer review comments and the public comments received (73FR60288). Persons can register free-of-charge with the NTP listserve (http://ntp.niehs.nih.gov/​go/​231) to receive notification when the final background document is posted on the RoC Web site (http://ntp.niehs.nih.gov/​go/​10091). As part of the RoC review process, two government groups will also conduct reviews of cobalt-tungsten carbide powders and hard metals; these meetings are not open to the public. Upon completion of these reviews, the NTP will (1) draft a substance profile for cobalt-tungsten carbide powders and hard metals that contains its listing recommendation for the 12th RoC and the scientific information supporting that recommendation, (2) solicit public comment on the draft substance profile, and (3) convene a meeting of the NTP Board of Scientific Counselors to peer review the draft substance profile.

Background Information on the RoC

The RoC is a Congressionally mandated document that identifies and discusses agents, substances, mixtures, or exposure circumstances (collectively referred to as “substances”) that may pose a hazard to human health by virtue of their carcinogenicity. The RoC follows a formal, multi-step process for review and evaluation of selected chemicals. Substances are listed in the report as either known or reasonably anticipated human carcinogens. The NTP prepares the RoC on behalf of the Secretary of Health and Human Services. Information about the RoC and the review process is available on its Web site (http://ntp.niehs.nih.gov/​go/​roc) or by contacting Dr. Lunn (see FOR FURTHER INFORMATION CONTACT above).

Dated: January 29, 2009.

Linda S. Birnbaum,

Director, National Institute of Environmental Health Sciences and National Toxicology Program.