n 1951, the United States built five military installations in Morocco, including the Nouasseur Air Base, now the Mohammed V International Airport. The United States kept secret an incident involving a nuclear bomb at the Sidi Slimane Air Base that could have caused thousands of casualties. The day after its independence, the Kingdom of Morocco pressured the United States to withdraw from its territory, which they did around 1963.
In 1950, just after the outbreak of the Korean War, the U.S. Department of Defense urgently needed to establish strategic air bases. There was also growing concern about the air defense alert system. According to NSC 68 (a top secret journal of the National Security Council), the Soviet Union would be preparing to launch devastating attacks by 1954, due to its growing stockpile of nuclear weapons and a newly developed bomber that could carry the atomic bomb.
The air bases agreement of December 22, 1950 stipulated that the United States would expand and use French facilities already on site in Morocco. At that time, it was impossible for the United States to negotiate with the Sultan. They had to negotiate the best deal with France. In January 1952, President Truman authorized the storage of non-nuclear weapons in Moroccan bases under French protectorate, where the B-36 and B-47 bombers were located (the French were not supposed to know). The Navy also raised the issue of the overseas deployment of nuclear weapons to the president.
On January 31st, 1958, at a Strategic Air Command base in Sidi Slimane, a B-47 bomber carrying a Mark 36 carried out a simulated takeoff during an exercise alert. The aircraft's left rear wheel failed when it reached about 55 km/h, causing the tail to collide on the runway and a fuel tank to break. The flames quickly reached the plutonium in the nuclear weapon on board and merged into the track.
The crew members escaped without injury. Although the firefighters had only 10 minutes to put out the flames, they focused on the plane much more than the nuclear bomb before withdrawing under the orders of the commanding general of the air base. The plane continued to burn for 7 hours.
The Mark 36 bomb did not explode but there was some contamination in the immediate area of the accident. After the plane and the asphalt underneath were removed, the runway collapsed. A fire truck and their uniforms had slight alpha contamination until detected.
Following the incident, exercise alerts were temporarily suspended, and the B-47 aircraft were checked for faults.
The Americans felt it would be in their best interest to keep information about the incident confidential. An American officer declared that “any revelation about the transport of nuclear weapons by our planes abroad would have negative consequences and would offer great opportunities for Soviet propaganda”.
The Americans concluded “[that] it was agreed that the Department should advise the Pentagon that we do not agree to the publication of a statement regarding the Sidi Slimane incident”, but the ambassador still informed senior Moroccan officials and King Mohammed V of the incident for their confidential information. Shortly after the incident, a small official denial was communicated to The New York Times.
The director of the European Regional Affairs Office was concerned about what happened in Sidi Slimane because he was not aware of any evacuation exercises. “The reports from the Rabat embassy and in the press referring to (an) evacuation of the base rather surprised us because no mention had been made of such a procedure”.
The American Embassy in Paris replied: “In the case of the Sidi Slimane incident, the commander-general chose to take advantage of it to put into practice his evacuation plan. It is unfortunate that this evacuation practice was linked to a plane carrying a nuclear weapon and that this fact became known”.
So the Americans finally chose to deny that a nuclear bomb could have killed hundreds, or maybe thousands.
https://unredacted.com/2013/10/09/document-friday-narrative-summaries-of-accidents-involving-nuclear-weapons/
https://nsarchive2.gwu.edu/nukevault/ebb442/
https://nsarchive2.gwu.edu/nukevault/ebb442/docs/doc%205A.pdf
https://nsarchive2.gwu.edu/nukevault/ebb442/docs/doc%205B.pdf
https://thebulletin.org/2014/03/accidents-will-happen-an-excerpt-from-command-and-control/
https://nsarchive2.gwu.edu/NSAEBB/NSAEBB197/nd-9.pdf
https://nuke.fas.org/norris/nuc_81010001a_n22.pdf
https://history.state.gov/historicaldocuments/frus1955-57v18/d193