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New documents reveal story behind green run

Nuclear Monitor Issue: 

(October 30, 1992) On the night of December 2, 1949, the filters in the stacks at the US nuclear weapons plant at Hanford, in Washington state, were turned off and 11,000 curies of iodine-131 were released directly into the atmosphere.

(381.3733) WISE Amsterdam - This secret experiment was called Green Run because it involved dissolving fuel that had been cooled only 16 days as compared to the normal 90 days (current practice is at least 180 days). The longer the cooling time, the more the radiation levels (especially iodine-131) would decrease.

Green Run remained a government top secret until 1986, when it was mentioned in historical Hanford documents which were released to the public in response to requests by citizens groups. In May 1989, the Department of Energy released most of the Green Run report in response to a Freedom of Information Act (FOIA) request filed by the Hanford Education Action League (HEAL) but important details were kept secret.

In 1991, the US Air Force declassified some additional sections of the Green Run report. These sections revealed at least one significant detail: there had been "previous tests." Unfortunately, the Green Run report provided no more information and only referenced another document. In late August of this year, in response to another FOIA request filed by HEAL, the Air Force declassified most of this document.


A report was released last year which revealed that thousands of Hanford, Washington residents may have received potentially harmful doses of radiation in the 1940s. The releases of radioactive iodine-131 from 1944 to 1947 were "significant enough to strongly justify a thyroid dose study," said John Till, a nuclear physicist and chair of a panel investigating the situation at Hanford.

The first phase studied airborne radioactive iodine-131 emissions from 1944-47 and radioactive cooling water poured into the Columbia River from 1964-67.

In a three-year period covered by the report, the Hanford iodine-131 emissions totaled 450,000 curies of which 340,000 were released in 1945. The panel had not yet examined releases after 1947 n including the December 1949 "Green Run", a deliberate experiment which released thousands of curies of radioactive iodine and other fission products.

The Spokesman-Review (US), 7 Dec. 1991

The document, from the Oak Ridge National Laboratory (ORNL) in Tennessee was titled "An Aerial Survey of Radioactivity Associated With Atomic Energy Plants" and published in April 1949 (ORNL-341). It details secret tests to detect airborne radiation from the nuclear weapons plants at Hanford and Oak Ridge and involved monitoring of radiation from plutonium separation plants by aircraft. These tests detected the releases from routine plant operations and were conducted from November 1948 through March 1949.

The Oak Ridge tests
Aerial surveys in Oak Ridge were the first in this series of tests of monitoring equipment. They were conducted in late 1948 and early 1949 and detected radioactivity in the atmosphere as far as 17 miles downwind from ORNL Chemical Separation pools used to dissolve reactor fuel.

At ORNL, 1300 curies of iodine-131 were released each time the fuel was dissolved. Background data in the document states that 150 pounds of reactor fuel were dissolved with a five day cooling period.

The document also notes that filters in the stacks would reduce the amount of iodine released to the atmosphere, although "the efficiency of the filtering is not known." "This was apparently a routine operation," noted Steve Smith of the Oak Ridge Environmental Peace Alliance (OREPA). "We know it happened at least a dozen times, we assume the operation had been going on for at least four years."

One alarming point about the Oak Ridge operations is that the fuel processed had only been cooled for five days. The Green Run fuel was cooled for 16 days, and the normal procedure at Hanford was to cool the fuel for at least 90 days.

"A major question hanging in the air is: Why was Oak Ridge dissolving with such a short cooling period?" noted Jim Thomas, Research Director for HEAL in Spokane, Washington. He added, "Even if they had filters, fuel this green could have saturated the filters quickly."

The US Department of Energy's office in Oak Ridge has refused to release the document locally. The document, listed as an Oak Ridge document, is publicly available in Washington State, but not in Oak Ridge even though it was originally written by ORNL scientists.

Ralph Hutchison of OREPA states that "This information will be crucial for the Oak Ridge Health Study."

The Hanford tests
The test flights conducted at Hanford in March 1949 had expected to detect radiation for several hundred miles downwind, perhaps even as far as a thousand miles. The test group was surprised when they could not even detect airborne radiation at the Richland airport, about 35 miles from the Hanford plants. Their inability to detect Hanford radiation was due to relatively crude monitoring equipment and Hanford's newly installed filters.

The ORNL-341 report recommended repeating the test at Hanford by disconnecting the plant filters and increasing the radiation released. This was done for Green Run.

The 1944 Hanford test
Documents declassified in August of 1987 indicated that the US Army Corps of Engineers deliberately released several hundred curies of radioactive iodine (iodine-131) at Hanford in 1944, five years before Green Run. The wartime research, for which there was no public warning, was intended to determine how far the winds would carry radiation in eastern Washington, a report indicates. The Army wanted to test how well its measuring devices could detect iodine, a telltale sign of plutonium production.

The document also lists accidental releases of radiation to farming communities in the Wahluke Slope area east of Hanford n home of the Hanford "downwinders" who contend today that their health problems are linked to past radiation emissions.

The experiment was conducted during the Manhattan Project; the top-secret effort to produce the atomic bombs which were dropped in Japan in 1945. It took place during the first reprocessing of plutonium in December 1944.

Carl C. Gamertsfelder, a leading radiation control manager at Hanford in the 1940s and '50s, said that the fuel used contained more iodine than usual because it had been cooled only about half as long as normal.

Detailed records of the experiment, which would show where the iodine was dispersed, were either lost or destroyed.

Information still missing
Judging from the context of the material deleted from this most recently released report, it appears that the Air Force still considers the identity of those directing the tests to be a matter of national security. Jim Thomas, HEAL's Research Director, commented: "We still don't know who authorized the Green Run or these previous tests and now we have the first documentation of potentially serious iodine releases from Oak Ridge."


  • Perspective, number 10-11, summer/fall 1992, p.21
  • GreenNet, nuc.facilities, 30 August 1992 and September 1992
  • The Spokesman-Review, 24 Dec 1987.

Contacts: HEAL, 1720 North Ash St., Spokane Washington 99205-4202, USA; tel: +1 509 326 3370.