The Communications Room in the Diefenbunker was a highly secure space essential for relaying top-secret military intelligence and orders during a nuclear crisis.
Smoking was permitted in the bunker until the 1980's
The Ottawa Semi-Automatic Exchange—known as OSAX—was built into the Bunker in 1981 to replace a larger facility on the 400 level. OSAX was the hub of military communications, connecting the bunker to a domestic and international network of receiver stations.
Once the doors were shut, the metal-clad room becomes what is known in the military as a “Faraday Cage and can withstand the electromagnetic pulses emanating from a nuclear blast that would otherwise disable or destroy electronic devices. Entrance to this room was limited to those with top-secret clearance.
After a nuclear blast, officials entering the Diefenbunker would undergo a two-stage decontamination process involving a cold shower in full clothing, disposal of contaminated items, and a hot shower, followed by a radiation check with a Geiger counter. This area, marked by yellow paint to indicate lead-lined walls, was a self-contained unit designed to prevent radioactive contamination from spreading to the rest of the bunker.
The blast tunnel entrance. The doors to the actual bunker are perpendicular to this tunnel which reduces the effects of a nuclear shock wave.
**Photographs taken with permission from the Diefenbunker: Canada’s Cold War Museum. Historical details provided by the museum.**
Medical facilities were equipped as a fully functioning hospital, able to perform every procedure except for open heart surgery and brain surgery. Dr. Barry Bruce who was stationed at the Diefenbunker became one of the founding members of the museum.
The War Cabinet room served as the decision-making hub for Canada’s emergency government during a national crisis, positioned between the military-focused Federal Warning Centre and the civilian-focused EMGOVSITCEN. It coordinated both types of intelligence to issue official orders, which were then processed by the Secretariat and distributed to the appropriate authorities.
Privacy was extremely limited in the Diefenbunker, with only the prime minister and governor general having private suites. The prime minister's quarters included an office, bedroom, and bathroom, from which national leadership would have been conducted during a nuclear crisis. Built during John Diefenbaker’s time in office (1957–1963), the Bunker reflected his efforts to prepare Canada for Cold War threats, despite public skepticism. Strict rules forbade family members from the bunker. This emotional dilemma affected all staff, who were required to make separate safety arrangements for their families.
Toilets in the Diefenbunker are built to withstand a nuclear bomb. They are mounted on one-inch thick rubber that is welded to the floor. All the plumbing connections to the toilet are flexible instead of rigid.
Diefenbunker: Canada's Cold War Museum
The Diefenbunker, officially known as the Central Emergency Government Headquarters, was built in the late 1950s during the Cold War as part of Canada’s preparations for potential nuclear conflict. Located in Carp, Ontario, just outside of Ottawa, it was commissioned by Prime Minister John Diefenbaker and designed to house key government and military officials to ensure the continuity of government in the event of a nuclear attack. Constructed in secrecy between 1959 and 1961, the four-storey, 100,000-square-foot underground bunker was equipped with secure communication systems, supplies, and infrastructure to support occupants for up to 30 days. Though never used for its intended purpose, the Diefenbunker operated in various official capacities until it was decommissioned in 1994. It was later transformed into a museum and now serves as a national historic site.
The mural in the dining hall/recreation room, original to the bunker, was one of a few that has survived. The idea was that this was like a window into the outside world and a reminder of what personnel were protecting, as there were no actual windows underground in the bunker.