EPA adopts LNT: New historical perspectives

Area of Science:

• Radiation health effects
• Environmental policy
• History of science

Background:

• The linear non-threshold (LNT) model is a key component of radiation risk assessment.
• The United States Environmental Protection Agency (EPA) adopted the LNT model for policy in 1975.
• Previous National Academy of Sciences (NAS) reports influenced EPA's decision.

Purpose of the Study:

• To historically assess the adoption of the LNT model by the EPA.
• To examine the influence of prior NAS radiation advisory panels on the EPA's decision.
• To highlight unrecognized recommendations from the 1960 Biological Effects of Atomic Radiation (BEAR) panels.

Main Methods:

• Historical analysis of scientific reports and policy documents.
• Review of recommendations from NAS radiation advisory panels (1956, 1960, 1972).
• Assessment of media, congressional, and scientific community responses to panel recommendations.

Main Results:

• 1960 BEAR panels' recommendations against LNT for cancer risk due to limitations and uncertainties were largely ignored.
• These recommendations were not promoted by sponsors and received minimal attention.
• The 1972 BEIR I report focused on the 1956 BEAR panel's linearity recommendation, overlooking the 1960 findings.

Conclusions:

• The EPA's 1975 adoption of the LNT model was influenced by a selective focus on certain scientific recommendations.
• Unrecognized 1960 BEAR panel findings highlighting LNT limitations were disregarded.
• This historical assessment reveals significant factors in the establishment of radiation policy.