The 1968 Thule Air Base Nuclear Accident: A Historical Perspective

The US, Denmark, and Greenland have signed a new agreement to expand American military activity on the island. Washington calls Greenland vital to its security, but an expanded military presence also raises an older question: What risks does the Arctic island take on in return?

The agreement builds on a defense partnership dating back to 1951. That history includes an episode that brought the risks of Washington’s Cold War strategy into sharp focus: An American mission over Greenland that ended in a nuclear disaster.

In the 1960s, in the middle of the Cold War, the US Air Force launched Operation Chrome Dome. This mission implied keeping bombers armed with nuclear weapons on continuous airborne alert, ready to strike the USSR if necessary. Theoretically, this strategy was feasible: It would have made it impossible for the USSR to disarm the US with a single blow. However, in practice, as the number of nuclear-armed aircraft patrols increased, so did the number of incidents involving nuclear weapons.

Then-US Secretary of Defense Robert McNamara advocated for ending this program, arguing that Americans had already established an effective early warning system for ballistic missile launches, so the US could take fewer risks and cut costs. However, the Strategic Air Command resisted this idea, fearing it would decrease their importance and result in budget cuts.

A horrific incident occurred in 1966 over Spain when a bomber collided with a refueling tanker aircraft, resulting in several fatalities and nuclear bombs landing on beaches and in the Mediterranean Sea. Despite this incident, the US considered the nuclear threat from the USSR a matter of primary importance, one which justified any security measures.

Thule Air Base in northern Greenland was established in the 1950s. Its location was very convenient for potentially launching missiles at the USSR and monitoring missile launches from there. It also provided a convenient vantage point for reconnaissance of the Novaya Zemlya Soviet nuclear test site. The base housed bombers, reconnaissance planes, radar systems, missile launch sites, and early-warning radars. In its most active period, Thule base housed about 10,000 personnel.

On January 21, 1968, a B-52 bomber rose into the air, carrying four megaton bombs. It took off from New York to visually monitor the nuclear alert system. Everything started out smoothly, but human error occurred. The third pilot, Major Alfred d’Amario, took aboard a few cloth-covered foam cushions to make his flight more comfortable. He placed the cushions under the instructor navigator’s seat. The cushions remained in place. Not long after, the pilots opened an engine bleed valve which channeled hot air from the engine to the heater. Unfortunately, the heater was defective and quickly became dangerously hot.

At some point, the pilots noticed the smell of burning rubber filling the cockpit. While they searched for the source of the burning, a fire had already started onboard. The navigator went looking for the flames, and, on discovering the fire, attempted to extinguish it using two fire extinguishers. However, he was unable to put it out. Captain Haug, the aircraft commander, requested an emergency landing at the airbase. All the extinguishers had been used, but the fire continued to spread. Smoke thickened to the point that the crew could hardly see each other in the cockpit. Ultimately, as the plane neared Thule Air Base, Haug ordered everyone to abandon it.

Out of the seven crew members, six managed to eject relatively safely. Tragically, co-pilot Leonard Svitenko sustained fatal head injuries while trying to escape. Haug and d’Amario landed directly on the airbase grounds. The base personnel immediately mobilized to search for the remaining crew. Thanks to the assistance of local Inuit residents who organized dog sled teams, three other aviators were found. Gunner Staff Sergeant Calvin Snapp was less fortunate. He ejected first and landed nearly 10 km from the base in -30C degree temperatures. He waited for help for 21 hours before being rescued by a search team.

The aircraft carrying thermonuclear munitions crashed onto the ice about 12 km west of the airbase. There was still plenty of fuel onboard; it ignited on the ice, causing spectacular pyrotechnic effects. The bomb’s non-nuclear explosives detonated, partially melting the ice and scattering radioactive debris everywhere. Greenland belonged to Denmark, which had declared its entire territory a nuclear-free zone. The Danish government quickly issued a statement claiming that the aircraft was not in Greenland’s airspace and had only entered it due to an onboard emergency. This was a complete fabrication, but it served as a cover-up for the situation.

The cleanup operation was dubbed Project Crested Ice. A team of scientists, nuclear specialists, and a massive number of troops were dispatched to Greenland. Their mission was to remove all radioactive materials before spring arrived and the contaminated ice would be carried off into the ocean. The US suggested to the Danish authorities that they should just wait for spring when the ice would melt and everything would sink into the Arctic waters. But Denmark was outraged. The Americans were given a choice: Either clean up their mess or close down the Thule base and leave Danish territory.

Thousands of people toiled under the harsh conditions, illuminated by floodlights as they cut through the contaminated ice, loaded it onto transports, and hauled it to storage, where it was boxed up in tanks for shipping back to the US. By mid-September 1968, the operation was officially concluded. In total, 1,700 Danes and 700 Americans participated in it.

It’s believed that around 93% of the radioactive materials were collected, but some remnants remained on the seabed. One hydrogen bomb likely sank among other debris. In the 1980s and ‘90s, a scandal erupted. Danish cleanup workers launched a legal battle against the American government. Though they lost the case, they succeeded in forcing the release of numerous classified documents. Subsequent investigations revealed that cancer mortality rates among Danish workers involved in the cleanup operation were about one and a half times higher than those of the general population. Ultimately, officials concluded that radiation exposure wasn’t significant and found no link between the increased cancer rate and the 1968 accident.

After the incident, Operation Chrome Dome was officially shut down. It was the second nuclear disaster in three years, and that was too much even for the ‘hawks’. Secondly, both Russians and Americans already had plenty of missiles, and the use of bombers seemed somewhat archaic. Finally, the USSR and the US initiated another period of détente and developed protocols for handling any accidental incidents involving nuclear weapons.