Foundations of Construction: Earth-shattering boom in 1958 Ottawa led to tighter regulations

ottawa gas explosion image
“October 25, 1958, at about 8:17 am, flipping on the basement lights ignited a disastrous explosion from a leaking natural gas pipe in the Addressograph-Multigraph building, Slater Street, Ottawa.” Photographer unknown/Urbsite.

By Susana McLeod

Special to Ontario Construction News

Smaller requirements may erupt into big disasters when duties are forgotten or missed on the job schedule. Upgrading to natural gas in Ottawa in early 1958, the older coal gas lines were decommissioned. Throughout the year, the project appeared to go well… until an earth-shaking explosion at the Addressograph-Multigraph building on Slater Street nine months later. Demolishing many buildings, the blast caused injuries and killed one man. The boom ignited further provincial oversight and tighter regulations.

Gathering cleaning supplies, the Addressograph janitor noticed an unpleasant scent just after 8:15 on Saturday, October 25, 1958. “I smelled gas that seemed to be coming from the far end of the basement,” said William Anderson from his hospital bed, according to Patrick Best of Ottawa Citizen, October 27, 1958. The janitor flipped on the light switch and “when I went to check it there was a rumble and a terrific explosion.”

Since it was a weekend morning, fewer people were in the area. Along with the janitor’s injuries, about 40 others received nasty injuries from flying glass and debris. Only a few blocks from Parliament Hill, several Slater Street buildings were left in ruins—twisted metal beams, shattered wood, and crushed glass. Windows in other buildings were blasted into piercing shards.

The Addressograph offices were destroyed. Nearby, Meyers Motors was demolished, as was the Odeon Theatre on Bank Street that backed onto the Addressograph building. Across the street next to the Jackson Building, a row of houses was hopelessly damaged from the explosion. Yet it could have been worse.

“The Jackson Building, where thousands of civil servants worked, situated at the corner of Slater and Bank Streets across from the Addressograph building, was also severely damaged,” wrote James Powell in Today in Ottawa’s History. “Virtually all windows were blown out; debris, sent high in the sky by the force of the blast, littered its roof.” As well, “all 12 elevators were jammed in shafts.”

Firefighters, government and gas company officials, and crews arrived to secure the site. Checking for gas leaks, Ottawa Gas Company workmen drilled holes at intervals into the pavement of surrounding streets. If readings indicated high gas vapour levels, the roadways were excavated “and new ‘sleeves’ put around time-worn couplings.” While those leaks were troubling, they were not the problem in the Addressograph-Multigraph building.

Previously used to carry coal gas, a service pipe in the commercial building’s basement should have been decommissioned, plugged, and sealed off. When natural gas was brought to Ottawa in January 1958, old gas mains were reused, with the gas introduced via 1-1/4-inch piping.

The Addressograph’s old pipe was missed during the decommissioning process. It “had been forgotten; employees in the building believed it to be a rusty, unused, water pipe,” said James Powell in “Remember This? The Slater Street Explosion,” City News, October 26, 2020.

“Although the pipe had been blocked over time by sludge and debris, the natural gas introduced into the mains gradually eroded the stoppage,” added Powell. The gas finally escaped, flowing silently into the building’s basement. The spark from the light switch was all that was needed to cause deadly havoc.

“Ironically,” said Powell, “just two days before the explosion, Ottawa Gas has assured Ottawa’s Board of Control that ‘no explosion hazards’ existed ‘in relation to the Ottawa Gas Company’s mains in the city streets.’”

Convening an inquest, the coroner’s jury developed a list of recommendations. The city’s natural gas firm was assigned with capping the many retired service lines and instructed to perform disconnections outside of the buildings. “Over the following year, Ottawa Gas complied, disconnecting more than 2,000 disused gas lines, and installing 1,000 shut-off valves.”

Another significant recommendation was for a new board be set up to handle installation permits for natural gas distribution systems, plus to inspect, keep plans and update the records of underground pipelines and mains in municipalities, noted Powell.

Established by Ontario Fuel Board Act, 1954, the original Fuel Board’s mandate was both administrative and judicial. Six years later, the Act was repealed. The Energy Act, 1960 and the Ontario Energy Board Act, 1960 (OEB) replaced the Fuel Board on Sept. 1, 1960. Controlling natural gas rates for distribution, transmission, and storage, OEB also tightly regulated construction of pipe lines for oil and gas.

The second part of the 1960 Energy Act provided that construction of pipe lines could not be undertaken until required approvals were received. The OEB had authority to revoke, suspend, or reinstate “licences, permits or registration,” and “could make orders granting leave to construct pipe lines for the transmission of oil or gas.” Land expropriation for pipeline construction was under the OEB’s purview as well.

Many lawsuits followed, and janitor William Anderson died from third-degree burns. Regulations limit the horrific events, but human activity with natural gas still presents risks.

© 2023 Susanna McLeod. McLeod is a Kingston-based freelance writer who specializes in Canadian History.


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