298. Memorandum From the Assistant Director of the Science and Technology Bureau, Arms Control and Disarmament Agency (Keeny) to the Director of the Arms Control and Disarmament Agency (Smith)1 2


  • Venting from AEC Nuclear Test of December 18, 1970 (BANEBERRY)

As detailed in the attached memcon, the Canadians reported having detected radioactive debris attributable to venting from the U.S. nuclear test BANEBERRY of December 18, 1970. The Canadian representation was oral and in low key, and they affirmed that the Canadian government had no intention to make a formal protest or to conceive of the event as a violation of the LTBT. Nevertheless, the representation is noteworthy in that it marks the first time a foreign government, other than the USSR, has officially approached the U.S. government concerning the detection beyond U.S. borders of radioactivity debris from a U.S. nuclear test.

In the meantime, the AEC has suspended further testing at the Nevada Test Site until it has reviewed the BANEBERRY test in detail and is convinced that every reasonable precaution has been initiated to reduce the probability of a similar future occurrence. Chairman Seaborg’s memorandum for members of the NSC Undersecretaries Committee, dated January 11, 1971, stated that the AEC hopes to complete this review by the end of January 1971, however, discussions with the AEC staff this morning indicated that testing will be suspended until at least 1 March 1971.

The release of radioactivity from BANEBERRY began at approximately H+3.5 minutes, from a crack in the earth, opening up after detonation in a southwesternly direction from the emplacement hole. Although it is too early to determine the [Page 2] cause of radioactive release, two possibilities which are being investigated are (1) an anomalous geologic situation or (2) unexpectedly high yield from the device.

The venting was rather widely publicized. The Environmental Protection Agency stated that radioactivity was traced to the Canadian border at International Falls, Minnesota, but presented no health effects.

The Soviets, on January 6, 1971, made an oral representation on this venting, but did not claim to have detected radioactive debris from it.

  1. Source: Washington National Records Center, Office of the Director, Subject Files of the Former Executive Director Office, January–December 1971: FRC 383–98–5, Underground Nuclear Testing–Venting December 1970–December 1971. Drafted by P.J. Long (ACDA/ST). The attached memorandum of conversation is not published. The Canadian minister stated that their readings did not indicate conclusively that the increase in radioactivity was a result of venting from the Nevada tests, but they considered it probable because the radioactivity resulted from “fresh venting.”
  2. Keeny discussed the Canadian reports of radioactive material detected in the atmosphere resulting from U.S. venting following the December 18, 1970 Baneberry underground nuclear test.