History of the Report on Carcinogens

a stack of four RoCs

Key Milestones


Congressional Mandate

Section 301(b)(4) of the Public Health Service Act, as amended, requires that the Secretary of the Department of Health and Human Services (DHHS) publish a report that identifies substances that pose a cancer hazard for people in the United States. The Report on Carcinogens (RoC) lists:

  1. All substances that are known to be human carcinogens or may reasonably be anticipated to be human carcinogens; and
  2. All substances to which a significant number of US residents are exposed.


First RoC published


Annual requirement for report changed to biennial

Historical Highlights of the Report on Carcinogens Criteria Listing Review Process

Since the RoC's inception in 1978, NTP has used scientifically rigorous processes and established listing criteria to evaluate substances for the RoC. The Board of Scientific Counselors (BSC) and the public have provided input leading to several evolutions of the RoC review process and listing criteria.

Pivotal Public Events


The following schematic describes the key elements of the RoC listing criteria and the review processes used for specific editions of the RoC. An accessible version of the schematic is also available.

Graphical schematic of the Report on Carcinogens listing criteria and review processes

Narrative Describing Report on Carcinogens Schematic

The schematic shows the listing criteria and the review process.

Listing Criteria

3rd Report on Carcinogens (1982) – 7th Report on Carcinogens (1994)

Formal criteria for two listing categories (known and reasonably anticipated to be a human carcinogen) based on evaluation of cancer studies in humans and experimental animals.

8th Report on Carcinogens (1998) – Present

Criteria expanded to include consideration of all relevant information such as mechanistic data. Approved by the Secretary, HHS in 1996.

Review Process

2nd Report on Carcinogens (1981) – 4th Report on Carcinogens (1985)

No formal review process: Collaborative effort by NTP and its interagency partners.

5th Report on Carcinogens (1989) – 7th Report on Carcinogens (1994)

Formal review process established.

  • Two federal scientific review committees established:
    1. NIEHS/NTP Scientific Review Committee
    2. Interagency Scientific Review Committee
  • NTP Executive Committee review added

8th Report on Carcinogens (1998) – 11th Report on Carcinogens (2004)

External scientific and public inputs added:

  • NTP Board of Scientific Counselors (BSC) Report on Carcinogens Subcommitee established: External review in a public forum
  • Formal process for delisting a substance from the Report on Carcinogens
  • Opportunities for additional public input throughout the process

12th Report on Carcinogens (2011)

Process revised to:

  • NTP BSC Report on Carcinogens Subcommitee ended
  • Ad hoc expert panel convened in public forum: Input on listing recommendation and peer review of draft background document
  • NTP BSC: Peer review of substance profile in public forum

13th Report on Carcinogens (2014) - Present

Process revised to:

  • NTP develops a concept document for each proposed candidate substance that is shared with public and reviewed by the NTP BSC in a public forum
  • NTP prepares a Report on Carcinogens monograph for each substance that includes the cancer hazard evaluation, listing recommendation, and the substance profile
  • Ad hoc review panel conducts external peer review of each Report on Carcinogens draft monograph in a public forum