January 28, 1931 was a typical cold winter day in Ottawa. In the late afternoon, kids were skating or playing hockey at the Sandy Hill rink. Twelve-year old Munroe Dingwall was skiing with friends down Somerset Ave. E. Most men were still at work and many housewives would already have started their dinner preparations.
At about quarter to five that afternoon, a series of explosions rocked the eastern half of the city. A crack opened in the roadway on Nelson Ave. between Somerset and Templeton streets. 28 manhole covers on Waverley, Nicholas, Nelson, Somerset St. E and River Rd. flew into the air, some high enough to cut power lines and shatter streetlights. Some houses were shifted from their foundations, many windows were broken and some plaster walls cracked. Although there were a few minor injuries, fortunately this time there was no fatality. Ottawa had just experienced its second sewer explosion in 20 months.
There were narrow escapes. Munroe Dingwall was lifted into the air by the explosion but landed unhurt in a snowbank. One manhole cover was recovered 45 yards away from where it had been installed. Gas fumes were reported in many houses but no fires.
The explosions hit most heavily in the vicinity of the Sandy Hill rink. Fred Arp, of 95 Templeton avenue, was the rink’s caretaker. He had been flooding the rink with a neighbour, Joseph Kealey, three days earlier “when a rumbling noise was heard in the sewers below the street. At the time, Mr. Arp said he remarked to Mr. Kealey, “There’s another explosion coming, Joe.” (Ottawa Journal, 28 January, 1931)
“Practically all the houses between Osgoode and Somerset, on Goulburn avenue, and between Sweetland and Strathcona Park, on Somerset street, had windows or doors open that evening in order to rid the houses and apartments of the strong odor of gas caused by the explosion”. (Ottawa Journal, 28 January, 1931)
On May 29, 1929, a similar series of explosions, also originating in Centretown and running east along Somerset St. through Sandy Hill, under the Rideau River and then north into Eastview (now Overbrook) and New Edinburgh, had also blown off manhole covers and damaged the sewers. That time, one woman, Mrs. Hannah Henderson, residing at 37 Templeton Ave. died from burns caused by the explosion and six people were injured, some seriously.
The damage caused by the second explosion was particularly extensive. A half-mile section of a 78” diameter brick sewer running along the Rideau River was shattered. To prevent backflow, sewage had to be poured directly into the Rideau River where it flowed under the ice until repairs could be completed.
While an investigation had been launched in 1929 and two more were in 1931, a cause for these explosions was never established conclusively. Many suspected carelessly dumped gasoline or a leak from a gas main but a suit by the City of the Ottawa Gas Company for damages failed for lack of evidence. The City had built three ventilating shafts to reduce the risk that dangerous gases would accumulate underground after the 1929 explosions but the 1931 reports indicated that numerous deficiencies remained in the way the City managed these risks. Sandy Hill residents had complained about gas smells in their basements for some time but had been unable to convince City authorities to act. Indeed, they continued to complain about gas smells for several days after the 1931 explosion, implying that dangerous gas levels were still present in the sewers.
After the second explosion, the City improved ventilation in the sewers and investigated complaints of gas smells more rigorously. The Commissioner of Works resigned but the City’s sewer engineer, who also had resigned, was re-instated in his old position.