300. Telegram 85171 From the Department of State to the Embassy in the Soviet Union1 2


  • Venting of Underground Explosions


  • State 2322

1. Acting Assistant Secretary Springsteen on May 14 called in Soviet DCM Vorontsov (in absence Ambassador) to reply to previous Soviet demarche on a U.S. nuclear test venting in December (reftel) and gave him a copy of the AEC report on the incident being released this afternoon.

2. In handing over AEC report, Springsteen noted:

Ambassador Dobrynin had raised the Nevada venting with Hillenbrand in January, at which time latter noted that a thorough investigation was being carried out and that any pertinent information would be brought to attention of Soviet Government.
U.S. had immediately suspended all underground testing after December incident. Intensive investigation [Page 2]has now been completed, and measures have been taken to reduce possibility of recurrence.
Our suspension of testing demonstrated seriousness with which USG views its obligations under Limited Test Ban Treaty and its determination to observe these obligations fully.
AEC is announcing decision to resume underground testing this afternoon and is releasing report on December incident to public. Fulfilling Hillenbrand’s assurance we now providing Soviet Government with copy of documents summarizing results of our investigation of December incident.

3. Springsteen also delivered following Aide-Memoire to Vorontsov, noting he was sure that our two governments agree that it is in interest of both to maintain integrity of Limited Test Ban Treaty and to take all necessary precautions to comply with it.

[Page 3]


The United States collected outside of the Soviet Union radioactive material directly associated with the Soviet nuclear explosions of November 4, 1970 and March 22 and 23, 1971.

In view of Paragraph 1 (B) of Article 1 of the Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space, and Under Water, the Government of the United States wishes to draw the attention of the Government of the Soviet Union to this matter, and to the importance of due precautions to insure compliances with that treaty. The United States Government would welcome any pertinent information the Soviet Government could make available about these events. END QUOTE

4. Vorontsov said he would pass Aide-Memoire to Moscow and inquired what caused venting in U.S. test. Springsteen replied that primary cause of venting in December test was an unexpected and abnormally high water [Page 4]content surrounding the detonation point. Springsteen concluded by reiterating that USG would welcome receiving any information which Soviet Government could make available on the three recent venting incidents referred to in Aide-Memoire.


  1. Source: National Archives, RG 59, Central Files 1970–1973, DEF 18–8 US. Confidential. It was repeated to USMission Geneva, Vienna, and AEC. Drafted on May 14 by Okun (EUR/SOV); cleared by Van Doren (ACDA); and approved by Springsteen (EUR).
  2. The Department reported on Deputy Assistant Secretary of State for European Affairs Springsteen’s May 14 meeting with Soviet Acting DCM Vorontsov. At this meeting the two men discussed the Soviet demarche over the venting of radioactive material from the December 18, 1970, Baneberry underground nuclear test.