NEW K-25 and S-50 Uranium and Fluoride Releases Public Health Assessment – Public Comment Version
ATSDR scientists present for public comment their evaluation of whether past releases of K-25 and S-50 Uranium and Fluoride from the Oak Ridge Gaseous Diffusion Plant could harm people living near the former facility, now the East Tennessee Technology Park.

Iodine-131 Releases

In 1942, the federal government established the Oak Ridge Reservation (ORR) to research, develop, and produce special radioactive materials for nuclear weapons. The X-10 site, currently known as the Oak Ridge National Laboratory (ORNL), was established in 1943 as a pilot plant to demonstrate plutonium production and separation. One major effort at the X-10 site was the production of radioactive lanthanum (RaLa), which took place from 1944 to 1956. During RaLa processing at the X-10 site, radioactive iodine was released as a byproduct into the air via stacks and vents. To address the community’s concerns, the Agency for Toxic Substances and Disease Registry (ATSDR) conducted a public health assessment to evaluate whether past, current, and potential future releases of iodine-131 (I-131) from the ORR could harm people living near the reservation. Drinking backyard goat’s and cow’s milk was determined to be the primary way in which people who lived near the ORR could have come in contact with I-131.

After reviewing the current literature, ATSDR concluded that individuals who were living near the ORR and who were at least 21 years of age* during the initial years of RaLa processing were not exposed to I-131 at levels that would have induced thyroid diseases, including thyroid cancer. However, because of limitations with the available data, ATSDR is unable to reach a definitive conclusion regarding the potential for I-131-related health effects to occur in the critical, sensitive population—those individuals who were under age 18,* who lived near the ORR during the years of RaLa processing, and who may have received a thyroid radiation dose in excess of 10 rads. Additionally, recently discovered historical air monitoring data from the early and mid-1950s and deer thyroid data from 1979 to 1989 suggest that I-131 released into the air from RaLa processing did not extend beyond the X-10 site boundary at levels that would constitute a public health hazard.

ATSDR does not expect any current or future exposures to I-131 from the X-10 site. Since 1991, no significant amounts of I-131 have been released to the air from the ORR. Any historical I-131 released from the X-10 site during the 1940s through 2005 has decayed completely or is currently not present in the ORR area at levels that pose a health hazard.

*The literature regarding health effects is inconclusive for individuals 18 to 20 years of age.

Iodine-131 Releases Basic Information (PDF, 733 KB)
This fact sheet presents the highlights of ATSDR's evaluation of potential health effects associated with iodine-131 releases from the Oak Ridge Reservation.

Iodine-131 Releases Technical Summary (PDF, 2 MB)
This fact sheet provides a technical summary of ATSDR's public health assessment on iodine-131 releases from the Oak Ridge Reservation.

Iodine-131 Releases Public Health Assessment – FInal Version (PDF, 2 MB)
This public health assessment presents ATSDR's evaluation of past, current, and potential future exposures to iodine-131 releases from the Oak Ridge Reservation. (May, 08).

X-10 Site Time Line (PDF, 63 KB)
This time line presents the major processes at the X-10 site, ORR environmental monitoring data, and public health activities at the X-10 site.

Iodine Public Health Statement
This is a summary chapter from the toxicological profile for iodine.

Iodine ToxFAQs
This fact sheet answers the most frequently asked health questions about iodine.

Iodine Toxicological Profile
This ATSDR toxicological profile characterizes the toxicology of iodine and provides information on adverse health effects associated with exposures to iodine.

ATSDR's Case Studies in Environmental Medicine: Radiation Exposure from Iodine-131
Case Studies in Environmental Medicine are a series of self-instructional publications designed to increase the primary care provider's knowledge of hazardous substances in the environment and to aid in the evaluation of potentially exposed patients.

Dr. Jerome Hershman's Presentation on Thyroid Disorders – Nodular Diseases and Cancer
This Web site summarizes a December 3, 2002, presentation by Dr. Jerome Hershman to the Oak Ridge Reservation Health Effects Subcommittee. Detailed information from Dr. Hershman's presentation on the thyroid and thyroid-related disorders, as well as comments made during group discussion, are included.

National Cancer Institute: Radioactive I-131 from Fallout
This Web site provides information and resources for people potentially exposed to iodine-131 through fallout from aboveground nuclear testing in the 1950s and early 1960s.

Are You a Hanford Downwinder?
This Web site provides educational resources for individuals concerned about past exposures to radioactive iodine released from the Hanford Nuclear Reservation. This site also provides information and resources regarding iodine-131.

The Hanford Thyroid Disease Study
This Web site provides information about a human health study that evaluated possible associations between exposures to iodine-131 released from the Hanford Nuclear Reservation and thyroid disease.

Hanford Video: Hanford Thyroid Disease Study – Final Report
This video presents the Hanford Thyroid Disease Study Final Report.

Ionizing Radiation Public Health Statement
This is a summary chapter from the toxicological profile for ionizing radiation.

Ionizing Radiation ToxFAQs
This fact sheet answers the most frequently asked health questions about ionizing radiation.

Ionizing Radiation Toxicological Profile
This ATSDR toxicological profile characterizes the toxicology of ionizing radiation and provides information on adverse health effects associated with exposures to ionizing radiation.

What Is a Public Health Assessment?
This fact sheet explains that an ATSDR public health assessment reviews available information about hazardous substances at a site and evaluates whether exposures to them could be harmful.

Exposure
This fact sheet answers questions about chemical exposures.

A Citizen's Guide to Risk Assessments and Public Health Assessments at Contaminated Sites
This document provides an overview of two different assessments commonly performed at hazardous waste sites-the risk assessment and the public health assessment. Both are required for all sites listed on the U.S. Environmental Protection Agency's National Priorities List (also known as "Superfund" sites).

Environmental and Occupational Medical Resources Fact Sheet
This fact sheet lists available medical resources for persons seeking medical assistance for an environment- or occupation-related illness or injury.

Programs

State Agency Links
List of ATSDR state cooperative agreement partners.