75. Aide-Mémoire From the Soviet Embassy to the Department of State1

No. 12

According to a report of the U.S. Atomic Energy Commission an underground nuclear explosion was conducted, on April 14 of this year in the state of Nevada,2 as a result of which there took place the ejection of earth to the surface and the penetration into the atmosphere of released radioactive materials. Inasmuch as this explosion was conducted under the “Plowshare” program and, as is indicated in this same report of the U.S. Atomic Energy Commission, a crater of large dimension formed at the site of the explosion—350 feet in diameter, 100 feet in depth, and [Page 200] forming a 60 foot lip—it is evident that with this underground nuclear explosion there took place not an accidental but a pre-planned ejection of a significant amount of earth and, consequently, a pre-planned ejection of radioactive materials into the atmosphere.

At the same time it is known that Article I (b) of the Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water contains the obligation of the parties of this Treaty to prohibit, to prevent, and not to carry out any nuclear explosions in any environment, including underground “if such explosion causes radioactive debris to be present outside the territorial limits” of the State which conducts the explosion. In this connection the Soviet Government requests that it be given more detailed information about the nuclear explosion conducted in the U.S.A. on April 14 this year since the assertion of the Atomic Energy Commission that the fallout of radioactive debris is within the boundaries of the U.S.A. is unconvincing because the Commission does not control the air streams carrying radioactivity, and there is reason to believe that with the conduct of this explosion there took place a violation of the Treaty banning nuclear weapon tests in three environments.

  1. Source: Seaborg, Journal, Vol. 10, pp. 437-438. No classification marking. A cover memorandum of conversation by Thompson (S/AL), April 29, reads as follows: “Dobrynin handed me the attached aide-mémoire concerning the recent Plowshare experiment. I made no comment.” (Ibid.) This aide-mémoire seemed to Seaborg “to be a political move, possibly in anticipation of discussion of mutual problems in conducting Plowshare programs.” (Ibid., p. 435)
  2. Reference is to Palanquin, a Plowshare cratering test, with a yield of 4.3 kt, which released radioactivity detected off site. (United States Nuclear Tests, July 1945 Through September 1992, p. 25)