Hanford Environmental Dose Reconstruction Project (HEDR) - Richland, Washington

What is the Dose Reconstruction Process?
  • Gather information about area of radiation exposure and assess data
  • Identify pathways of internal and external exposure
  • Determine methods of calculation to estimate screening doses and exposures
  • Develop methods to assess and estimate environmental doses
  • Determine risk of environmental exposures through selected calculation method
  • Document reconstruction procedures and results


CDC first became involved in the HEDR Project in 1992, when responsibility for the project was transferred from the Department of Energy to the Department of Health and Human Services. The purpose of the study was to address community health concerns by estimating the amount and types of radioactive materials that were released to the environment (via air and river pathways) from the Hanford Site and by estimating radiation doses to representative individuals within the communities downwind from Hanford.

Project Activities

CDC’s work on the Hanford Environmental Dose Reconstruction (HEDR) Project represents the federal government’s first comprehensive attempt to estimate the amount and type of radiation releases that people were exposed to during plant operations at the Hanford Nuclear Weapons Production facility in Washington State. CDC released the first estimated dose results pdf icon[PDF – 18.4MB] in April 1994. Then, CDC researchers used the mathematical computer model that was developed during the HEDR project to address some remaining community and scientific concerns. The dose estimation methodology developed during the HEDR project also was used by investigators conducting the congressionally mandated Hanford Thyroid Disease Study (HTDS) that was concluded in 2002.

Hanford Thyroid Disease Study (HTDS)

The Hanford Thyroid Disease Study was mandated by Congress in 1988. It is the first epidemiologic study to examine whether rates of thyroid disease are higher than normal among people exposed to releases of radioactive iodine from the Hanford site during the period of highest releases, 1944 through 1957. The HTDS consists of 5,199 people identified from records of births during 1940-46 to mothers whose place of residence was in one of seven affected counties in the state of Washington, and the Final Report of the HTDS was released in 2002.

Other Hanford Research

Two additional reports related to Hanford radiation releases were completed in January 2003:

Page last reviewed: January 3, 2014