Governing principles for the Committee's work

The Committee's Governing Principles were first approved at the sixty-first (21-25 July 2014) session, amended at the sixty-second (1-5 June 2015), sixty-ninth (9-13 May 2022) and seventieth (19–23 June 2023) sessions.


The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) was established by the General Assembly in 1955 in response to the international community’s growing concern over potential health impact of fallout from the ongoing and expanding atmospheric testing of nuclear weapons. Originally, the Assembly invited 15 United Nations Member States (now 31) to nominate scientists as Representatives to the Committee and tasked them with assessing exposures to atomic (or ionizing) radiation, and health effects from such exposures, and to report their findings to the Assembly. Whereas exposure to fallout from nuclear weapons testing became much less prominent over the decades, the Committee continues to evaluate exposures to the human population worldwide from all natural and man-made sources of ionizing radiation. It also reviews and reports on the current understanding of the biological effects of exposure to ionizing radiation at the molecular, cellular and tissue levels, as well as human health risks and effects on the natural environment.

The Scientific Committee does not develop policy or provide advice to governments or regional or international bodies. However, many governments and relevant bodies choose to make use of the Committee’s scientific evaluations for their own development of policies, e.g., with regard to health care, protection of the public and the environment, emergency preparedness, remediation of contaminated land, and decisions related to the use of ionizing radiation across the whole range of potential applications.

The subjects of the Scientific Committee’s scientific evaluations may in some cases be relevant to debates on issues that are contentious, controversial and politically charged. The Committee does not take a position in such debates; however, the Committee’s scientific evaluations may inform such debates. The Committee has established Strategic Directions [1] to provide high-level guidance for planning the Committee’s future work. The Strategic Directions outline scientific priorities for the next decade; and strategies that enhance the delivery of high-quality, robust, unbiased and transparent scientific evaluations. The value to the international community of the Committee’s scientific evaluations is dependent on the scientific rigour by which they are undertaken, but also on the credibility and scientific integrity of the membership of the Committee. Any real or perceived bias or conflict of interest among its membership would greatly undermine the credibility of the Committee’s scientific evaluations and reduce their value to the international community.

Representatives to the Scientific Committee, Alternate Representatives, Advisers, and the Committee as a collective, maintain high ethical standards in how they discharge their duties, and the Committee is administered in a way that promotes unbiased evaluations with high scientific integrity.

Representatives, Alternate Representatives and Advisers need to be aware of the expectations surrounding their conduct, as outlined in these Governing Principles, and the processes and procedures for the Scientific Committee’s work.

Mandate of the Committee

The Scientific Committee's mandate was first set out in the General Assembly resolution 913 (X) of 1955. Since the General Assembly resolution 3154 (XXVIII) of 1973, the Committee was further requested to consider the risks [2] of ionizing radiation from all sources. UNSCEAR reports are based on science and are neutral with respect to policy, although they may need to deal objectively with scientific and technical factors relevant to the application of particular policies. The Committee decides on priority areas for evaluation and records these in its programme of work.

The Committee is accountable to the General Assembly of the United Nations

The Committee is accountable as a whole to the General Assembly of the United Nations, and thus applies the fundamental values of the United Nations to its work and deliberations. The States members of the Committee have been selected by virtue of their ability to contribute to the work of the Committee and derive no additional political privilege above States not members of the Committee. The Committee concentrates its activities on fulfilling its mandate and on tasks allotted to it by the General Assembly. The Committee is ultimately responsible for its reports, and not the writers or experts who have prepared material for its scrutiny.

United Nations Environment Programme is responsible for servicing the Committee

The United Nations Environment Programme (UNEP) is responsible for servicing the Scientific Committee; it provides the UNSCEAR secretariat (further “secretariat”) whose head is the Secretary of the Committee. The secretariat provides important institutional continuity and centralized administrative and technical support. Inter alia, it prepares and services the annual sessions of the Scientific Committee, prepares draft documents for the Committee’s scrutiny, manages the funding allocated for the Committee's work, engages expertise as necessary, and ensures that United Nations protocols for processes and timelines are followed.

Membership of the Committee

Originally, the General Assembly invited 15 United Nations Member States to nominate scientists as Representatives to the Committee (31 States members of the Committee since 2022) [3] and tasked them with assessing exposures to ionizing radiation, health effects from such exposures, and reporting the findings to the General Assembly.

Further increases in membership of the Scientific Committee are considered by the General Assembly pursuant to paragraph 19 of Assembly resolution 66/70 of 2011, and the procedure detailed in paragraph 21 of Assembly resolution of 73/261 of 2018.

Members must demonstrate competence and integrity

Representatives, Alternate Representatives and Advisers are nominated by Governments on the basis of their scientific qualifications and experience; and are to perform scientific evaluations in accordance with established scientific procedures and values. They are to have in-depth knowledge on a broad range of relevant scientific and technical issues, to stay abreast of scientific developments, to foster effective support nationally, to apply sound judgement, and to communicate the conclusions of their reviews. They are also to:

  1. Act independently (although delegations are to provide coordinated input on the grounds of efficiency), and to discharge their duties without bias in relation to external pressures or interests that may be in conflict (real or perceived) with the Scientific Committee’s procedures and tasks;
  2. To guard the reputation of the Scientific Committee, and declare any potential conflict of interest and/or recuse themselves from decisions or judgements where these might jeopardize the impartiality of the member or of the scientific evaluation of the Committee;
  3. To act with integrity, applying a questioning and open-minded attitude, being respectful of differing viewpoints, communicating truthfully and honestly, and respecting matters of intellectual property;
  4. To provide and support the Scientific Committee in collecting, analysing and disseminating data on medical, occupational and public exposures to ionizing radiation for carrying out updates on scientific evaluations according to the agreed programme of work.

Officers of the Committee rotate and reflect an equitable geographical distribution

Officers of the Committee include the UNSCEAR Chair, three Vice-Chairs, and a Rapporteur, elected on two-year terms and with the intention of electing a new Chair after two years of service in that position. No individual should serve as an officer for more than six years. These officers are elected from among Representatives and Alternate Representatives with the necessary competence, experience and capability to discharge their duties as officers, and with due regard to geographical distribution. When the programme of work of the Committee focuses on a scientific issue that may be contentious, the Committee endeavours to take due care in its election of Chair and Vice-Chairs, and any other function of significance for carrying out the work, to avoid any real or perceived conflicts of interest.

The officers collectively constitute the Bureau of the Scientific Committee. The immediate past Chair, the Secretary and Deputy Secretary of the Committee, are advisers to the Bureau.

Committee’s annual session

The Scientific Committee meets in person on an annual basis, normally between April and June, at the Vienna International Centre in Vienna, Austria. The dates of the upcoming session are agreed in the closing plenary of the previous session and are included in the Committee’s report to the General Assembly. The UNSCEAR secretariat shall issue a Note Verbale including a preliminary Agenda for the session to all States members of the Committee and invited international organizations (Observers) not later than four months before the session. This will request the nomination of Representatives, Alternate Representatives and Advisers that demonstrate the required competence and integrity for the planned session. The UNSCEAR secretariat, working with the Committee’s Bureau shall prepare a detailed agenda for the session, shall propose appropriate Chairs and Rapporteurs from the nominated delegations, and shall ensure the distribution of session documents within required United Nations timeframes:

  1. Ten weeks before session for scientific evaluations being considered for approval for publication;
  2. Six weeks before session for all other documents tabled for Committee review and discussion during the session.

The UNSCEAR secretariat shall make travel arrangements for the nominated Representative of each States member of the Committee according to the United Nations rules and procedures.

Conduct of the Committee's work

The Scientific Committee’s scientific evaluations are undertaken in a variety of ways: this includes the work of consultants engaged by the secretariat under the oversight of the Bureau, groups of experts from within the Committee, or larger groups of experts comprising scientists nominated by United Nations Member States on a voluntary basis. These professionals are also bound by the same expectations of scientific qualifications, experience, procedures and values as members of the Committee. Review of drafts by delegations is an essential part of the Committee’s process to ensure quality.

The roles and responsibilities of the different contributors to the Committee’s scientific evaluations are outlined as follows:

The Committee

Major decisions of the Scientific Committee are taken in plenary meetings during the annual session. The Committee reports annually to the General Assembly on progress in conducting its programme of work, and the findings of its scientific evaluations.

For all scientific evaluations, the Committee will:

  1. Agree on the scope, objectives and project plan for the evaluation;
  2. Take decisions to conduct evaluations (scientific annexes) within its programme of work;
  3. Monitor progress at the Committee’s sessions to ensure that the evaluations are of high quality and independent in line with the mandate of the Committee, the Strategic Directions and these Governing Principles;
  4. Review and approve the scientific credibility of the evaluations before publication; and
  5. Report its scientific findings to the General Assembly.
A procedure for preparing the Committee’s scientific evaluations is detailed in the document Preparation of the Committee’s scientific annexes and reports for publication.

The Bureau of the Committee and its ad hoc working groups

The purpose of the Scientific Committee’s Bureau is to strengthen and facilitate timely and effective implementation of the Committee’s programme of work in accordance with its mandate, the Strategic Directions, these Governing Principles, decisions of the Committee, resolutions of the General Assembly and applicable United Nations rules and procedures. The functions of the Bureau are detailed in the supporting document Terms of Reference4 for the UNSCEAR Bureau.

The Bureau of the Committee will advise the secretariat (between sessions) and will:

  1. Take strategic decisions to remove obstacles to the effective progress of the agreed programme of work and resolve any related issues;
  2. Monitor the progress and recommend ways to improve both the methodology and content of the evaluations (with support from the ad hoc working groups);
  3. Endorse changes to project plans, organization and experts involved in evaluations;
  4. Direct the drafting of relevant components of the Committee’s report to the General Assembly;
  5. Advise the secretariat on public communication matters, and assist in outreach activities;
  6. Report to the Committee at the business meeting of the pre-session consultations.

The Bureau meets every 4–6 weeks between annual sessions to guide the implementation of the programme of work, to support the Chair and secretariat to prepare for the General Assembly, and to prepare for the annual session.

The Bureau is supported by two ad-hoc working groups that were established in accordance with the Strategic Directions to assist in optimizing working arrangements for the Committee’s scientific evaluations. The ad hoc working groups were originally envisaged in the Strategic Directions to provide:

  1. One group that supports the Committee’s work on biological, health and environmental effects and risks;
  2. One group that supports the collation and analysis of data on sources and exposures.

Following the implementation of these groups they have undertaken work in accordance with established Terms of Reference (ToR).5, 6 The Committee may give additional direction to the ad hoc working groups during the annual session and update their ToR as necessary. The ad hoc working groups report to the Bureau, which is accountable to the Committee for its work. Both groups are chaired by one of the Committee’s vice-chairs and undertake intersessional work to assist the Bureau in ensuring the timely implementation of the Committee’s programme of work and to consider priorities (on the basis of literature reviews and other developments) for the future programme of work.

UNSCEAR secretariat

The secretariat of the Committee will:

  1. Establish expert groups involved in evaluations and monitor their activities, in accordance with the project plan agreed by the Committee. The expert groups will comprise of a Coordinating Lead Writer, Lead Writers, and Contributing Writers. They will be supported by a Senior Technical Advisor and critical reviewers and a Project Officer from the secretariat. The roles of expert group members are included at the appendix;
  2. Engage consultants (Coordinating Lead Writer and Lead Writers) and ‘in kind’7 experts (including critical reviewers) and provide administrative support;
  3. Liaise with and collect data from Member States and international organizations in support of the scientific evaluations, and maintain the survey platform and network of National Contact Persons;
  4. Advise on relevant United Nations and UNSCEAR procedures, as appropriate;
  5. Ensure written and presentation quality of the evaluation and publication according to United Nations rules and UNSCEAR guidance;
  6. Make arrangements for writing and editing the scientific annex (incl. tables, diagrams, and references) and printing of the final report;
  7. Ensure engagement with international organisations providing input data for the evaluation, and respectively ensure acknowledgment of contributions in the scientific annex;
  8. Review, inform and monitor adherence on United Nations and UNSCEAR standards and guidelines for use of source materials;
  9. Manage the technical infrastructure to record proceedings, organise meetings (including online), and archive published information;
  10. Manage review of the peer reviewed literature and pre-final draft of the scientific annex, help in validating good scientific practice and share information with the Committee;
  11. Interact formally with Member States and international organizations;
  12. Disseminate the findings of the Committee and manage public outreach matters;
  13. Authorise citations of the final published scientific annex.

The Committee's scientific evaluations are available to all

The Scientific annexes underpinning the Committee’s reports to the General Assembly are available as United Nations publications but can also be downloaded freely from the Committee’s website, The Bureau and secretariat endeavour to communicate the findings of the Committee to the General Assembly, the scientific community (e.g. in conferences, webinars and scientific symposia) and the public as reasonably practicable. Members of the Committee take care to avoid confusing any audience as to the scientific position of the Committee as a whole, or reflecting their personal views in the name of the Committee. They follow the UNSCEAR policy strategy as detailed in the Committee’s public information and outreach strategy8 and may not represent the Committee without approval through the secretariat.


1 Updated and agreed by the Committee at its sixty-sixth session (10–14 June 2019).

2 In the context of (radiation-related) health effects, risk refers to the probability that an event of interest (e.g., onset of cancer) will occur (i.e., it is prospective) during a given time period (e.g., the rest of life following an exposure). Risks can be estimated using evidence from epidemiological investigations of disease rates in previously exposed populations (i.e., based on past observations). The results from such retrospective analyses often are used, with appropriate modifying and adjustment factors, to make inferences about the risk for other exposure situations involving different populations for which direct epidemiological data on the dose-response relationship are not available (UNSCEAR 2012 Report (2015)).

3 The Scientific Committee was originally composed of the following States members of the United Nations: Argentina, Australia, Belgium, Brazil, Canada, Czechoslovakia (later succeeded by Slovakia), Egypt, France, India, Japan, Mexico, Sweden, Union of Soviet Socialist Republics (later succeeded by the Russian Federation), United Kingdom of Great Britain and Northern Ireland and United States of America. The membership of the Scientific Committee was subsequently enlarged by the Assembly in its resolution 3154 (XXVIII) of 14 December 1973 to include the Federal Republic of Germany (later succeeded by Germany), Indonesia, Peru, Poland, and the Sudan. By its resolution 41/62 of 3 December 1986, the General Assembly increased the membership of the Committee to 21 members and invited China to become a member. In its resolution 66/70, the General Assembly further enlarged the membership of the Committee to 27 and invited Belarus, Finland, Pakistan, the Republic of Korea, Spain, and Ukraine to become members. In its resolution 76/75, the General Assembly further enlarged the membership of the Committee to 31 and invited Algeria, Iran (Islamic Republic of), Norway and the United Arab Emirates to become members.

4 Terms of Reference for the UNSCEAR Bureau, 14 June 2019.

5 UNSCEAR/65/10 "Concept of operation for the ad hoc working group on developing the Committee’s programme of work on effects of radiation exposure for the period 2020–2024”.

6 Terms of Reference for the UNSCEAR ad hoc working group on sources and exposure, approved at the sixty-sixth session (Vienna, 10–14 June 2019), amended at the sixty-ninth session (Vienna, 9–13 May 2022).

7 ‘In-kind’ experts are defined as experts who are supported by their home organizations to undertake work within expert groups. No financial payment is made to these experts and the contribution of their work is defined as ‘in-kind’.

8 UNSCEAR/66/8 Public information and outreach, including a strategy for 2020-2024.