National Toxicology Program

National Toxicology Program

History of the RoC

Congressional Mandate (1978)

In response to concerns from people within the United States regarding the relationship between their environment and cancer, in 1978 the U.S. Congress mandated, as part of the Public Health Service Act, (see Section 301(b)(4), as amended)[1], that the Secretary, Health and Human Services (HHS), publish a biennial report which contains:

  1. a list of all substances
    1. which either are known to be carcinogens or may reasonably be anticipated to be carcinogens and
    2. to which a significant number of persons residing in the United States are exposed;
  2. information concerning the nature of such exposure and the estimated number of persons exposed to such substances;
  3. a statement identifying
    1. each substance contained in the list under subparagraph (A) for which no effluent, ambient, or exposure standard has been established by a Federal agency, and
    2. for each effluent, ambient, or exposure standard established by a Federal agency with respect to a substance contained in the list under subparagraph (A), the extent to which, on the basis of available medical, scientific, or other data, such standard, and the implementation of such standard by the agency, decreases the risk to public health from exposure to the substance; and
  4. a description of
    1. each request received during the year involved
      1. from a Federal agency outside the Department of Health, Education, and Welfare for the Secretary, or
      2. from an entity within the Department of Health, Education, and Welfare to any other entity within the Department,
      to conduct research into, or testing for, the carcinogenicity of substances or to provide information described in clause (ii) of subparagraph (C), and
    2. how the Secretary and each such other entity, respectively, have responded to each such request.

Preparation of the Report on Carcinogens (RoC)

The Secretary delegated responsibility for preparing the RoC to the National Toxicology Program (NTP). The NTP is an interagency program within HHS and is headquartered at the National Institute of Environmental Health Sciences of the National Institutes of Health. Since its inception in 1978, the NTP has strived to improve its scientific review process for evaluating whether substances should be listed in the RoC.

Revisions to the Review Process and Listing Criteria: 8th RoC (1998)

In 1994, the NTP Director initiated a review of the RoC to (1) broaden input for the preparation of the report, (2) broaden the scope of scientific review associated with the RoC, and (3) provide review of the criteria used for listing substances in the RoC. The NTP began using the revised process and revised criteria with the 8th RoC, which was published in 1998.

The revised process included: (1) addition of an external peer review conducted by members of the NTP Board of Scientific Counselors in a public forum with opportunity for public comment, (2) opportunities for additional public input throughout the review process, and (3) establishment of a formal review mechanism for the consideration of removing (delisting) substances from the RoC.

This review of the criteria was open to the public and included participation by many interested parties, including academia, industry, labor, private organizations, and federal, state, and local agencies. In 1996, the Secretary approved the revised criteria, which allows for consideration of all relevant information, including mechanism of action, when making decisions about listing nominations in the RoC.

Public Meeting of Review Process (1999)

In response to comments from interested stakeholders on the listing criteria and the procedures used in review of nominations for the 8th and 9th RoCs, the NTP held a public meeting in October 1999 to revisit these issues. The NTP used this input to implement some changes in the review process for preparing future RoCs, but did not feel that changes in the listing criteria were needed at that time. The NTP responses to the public comments made at the 1999 meeting are posted on its website.

Revisions to the Review Process: 12th RoC (2007)

The NTP considered public comments received on the review process and listing criteria for the review of nominations to the 10th and 11th RoCs. and convened another public meeting in January 2004. Similar to the 1999 meeting, the NTP prepared and released responses to the public comments made at the 2004 meeting.

Following the 2004 meeting, the NTP revised the RoC review process for the 12th RoC to enhance the scientific development of the report and address guidance in the Office of Management and Budget (OMB) Peer Review Bulletin. The revised process has two important new elements: (1) public peer review of draft background documents by ad hoc scientific expert panels and (2) public peer review of draft substance profiles by the NTP Board of Scientific Counselors.

The proposed process was released for public comment in August 2006. Based on its consideration of the public comments received, the NTP finalized the review process and released it in April 2007. Both the public comments and the NTP response to these comments are available on the NTP website.

Editions of the RoC

The 1st RoC was published in 1980 and contained 26 listings. Each edition of the RoC is cumulative and consists of substances newly reviewed in addition to those listed in the previous edition. To date, a total of 12 RoCs have been published; the most recent, the 12th RoC, was released in 2011, and includes 240 listings, some of which are classes of related chemicals or agents.

1The original requirement for this report was established in November 1978 by the Community Mental Health Center Act, Amendments, Section 262, Public Law 95-622, Part E (pp. 3435-3436). An amendment in 1993 (42 US Code 241) substituted a biennial report for an annual report in the introductory provisions.

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The NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.