In 1987 – 88 and again in 2000 , reports surfaced in the Danish press that one of the bombs had not been recovered . SAC stated at the time of the accident that all four bombs were destroyed . In 2008 , the BBC published an article that was based on its examination of partly declassified documents obtained some years earlier , via the United States Freedom of Information Act . The documents appeared to confirm that within weeks of the accident , investigators realized only three of the weapons could be accounted for . One of the declassified documents — dated to January 1968 — details a blackened section of ice which had refrozen with shroud lines from a weapon parachute : " Speculate something melted through the ice such as burning primary or secondary . " A July 1968 report states , " An analysis by the AEC of the recovered secondary components indicates recovery of 85 percent of the uranium and 94 percent , by weight , of three secondaries . No parts of the fourth secondary have been identified . " The BBC tracked down several officials involved in the accident 's aftermath . One was William H. Chambers , a former nuclear weapons designer at the Los Alamos National Laboratory . Chambers headed a team dealing with nuclear accidents , including the Thule crash . He explained the logic behind the decision to abandon the search : " There was disappointment in what you might call a failure to return all of the components ... it would be very difficult for anyone else to recover classified pieces if we could n't find them . " In August 1968 , the United States military sent a Star III mini-submarine to the base to look for weapon debris , especially the uranium-235 fissile core of a secondary . A much bigger operation at Palomares off the coast of Spain two years earlier led to the recovery of a lost nuclear weapon from the Mediterranean Sea ; the B28FI bomb was lost for 80 days after a mid-air collision between a B-52 on a " Chrome Dome " mission and its KC-135 Stratotanker refueling aircraft . Christensen asserts that the purpose of the underwater search at Thule was obvious to the Danish authorities , contrary to other reports that suggested its true purpose had been hidden from them . At lower levels , however , the dives were surrounded by some confidentiality . One document from July 1968 reads , " Fact that this operation includes search for object or missing weapon part is to be treated as Confidential NOFORN " , meaning it was not to be disclosed to non-US nationals . It continues , " For discussion with Danes , this operation should be referred to as a survey , repeat survey of bottom under impact point . " Further indications of the search are apparent in a September 1968 interim report by the United States Atomic Energy Commission , which stated , " It was further speculated that the missing '' '' , in view of its ballistic characteristics , may have come to rest beyond the observed concentration of heavy debris . " This discussion was a reference to the unsuccessful search for the uranium cylinder of one of the secondaries
Palomares
1966 Palomares B-52 crash
1968 Thule Air Base B-52 crash