29 May 1929 and 28 January 1931

Almost ninety years ago, the City of Ottawa was rocked by two series of sewer explosions that occurred twenty months apart. The first happened on 29 May 1929, and the second on 28 January 1931. Both hit the same areas of town—Sandy Hill, Vanier (then called Eastview) and New Edinburgh—and caused extensive damage. There was also one fatality in the first set of blasts; many were injured. Despite three inquiries, the exact cause of the explosions was never conclusively determined though leaking illuminating gas used for lighting was believed to have been the culprit. However, a lengthy law suit launched by the City against the Ottawa Gas Company to cover the costs of the second explosions failed.

The 1929 explosions began shortly before noon on 29 May in the block bounded by Cartier, Frank, Waverely and Elgin Streets in the Golden Triangle neighbourhood of Centre Town, blowing out manhole covers in the area. The resulting fire ignited gas inside the main sewer line running eastward under the Rideau Canal, causing shaking, rumbling and venting through manholes on Templeton Avenue, Henderson Avenue and Nelson Streets in Sandy Hill, before travelling down St Patrick Street and into New Edinburgh on the other side of the Rideau River along Crichton, MacKay and John Streets to the sewage outlet into the Ottawa River. There were also a number of smaller blasts in the Eastview and Clarkstown areas (Vanier) between Montreal Road and Beechwood Avenue.

Headline, The Ottawa Evening Journal, 29 May 1929

At least twenty-eight manhole covers were blown in the air, some thirty to forty feet, before crashing to the ground. Clouds of smoke and vivid tongues of flame were reported emanating from the manholes. Mrs Anna Heyden, age 73, of 37 Templeton Avenue was killed when flames shot out of her kitchen sinkhole and ignited her clothes. Although she managed to flee her home, she later succumbed to her injuries in hospital. Around the corner at 192 Henderson Avenue, Miss Lilian Pettypiece, age 20, escaped a similar house fire with serious burns. She had been in her cellar choosing potatoes for lunch when she was enveloped by flames that shot out of a sewer connection. Despite choking fumes, she managed to stumble up the stairs to the outside where she was rescued. Many others were injured by flying glass blown from windows. The home of Captain Sam Blackler of the Ottawa Fire Department at 211 Henderson Avenue was rocked from its foundations by the force of a blast and was gutted by fire. Fortunately, nobody was hurt. Mrs Blackler suffered a narrow escape, however. She had just walked out of the kitchen a minute before it was wrecked. An apartment building at the corner of Somerset Street East and Chapel Street, which housed a grocery on the ground floor, also suffered serious structural damage. In New Edinburgh, St Martin’s Anglican Chapel on John Street was destroyed. In total, the sewer explosion caused roughly $40,000 in property damage.

Ottawa’s mayor Arthur Ellis was convinced that the explosions were not due either “to defects in the city sewer,” or to sewer gas (a mixture of hydrogen sulphide and other gases). Municipal leaders commissioned John Campbell from the Edison Illuminating Company of Boston to conduct an inquiry into the disaster. Campbell concluded that the exact nature of the gases that exploded might never be known as no tests were performed on gas in the sewers prior to the explosion. However, he pointed to two possibilities: i) gasoline vapours due to the improper disposal of gasoline by homeowners, leakages from the growing number of service stations in the area, and waste from dry-cleaners, or ii) a leak from a gas main. He noted that the Ottawa Gas Company had been digging for leaks prior to and during the day of the explosion. He added that the sewer explosion need not have been the result of a single big leak but could have been due to a number of small ones. While not specifically pointing the finger at illuminating gas, he added that the lack of soot deposits and the nature of the fire suggested a gas lighter than air was responsible; gasoline vapours are three times heavier than air whereas illuminating gas is half as heavy as air. Campbell was of the view that the exact point of ignition was in the Frank-Cartier Streets area. However, what caused the ignition would never be known. He postulated it could have been a lighted match, the backfire of an automobile, or a spark from a trolley wheel.

Rather than lay blame, which he argued was outside of the remit of his report, Campbell made a number of recommendations. These included the prompt investigation of complaints about gas smells (complaints prior to the explosion were apparently not investigate with any degree of diligence), the regulation of the sale of gasoline to homeowners, a prohibition on disposing of volatile fluids in the sewers, and the inspection of gasoline service stations. He also recommended the construction of ventilation stacks with fans to help dissipate volatile vapours in the sewers, and the hiring of additional staff by the City to keep up to date in the matter of inspecting, testing and the keeping of records.

The second series of sewer explosions began at roughly 4.30 pm on 29 January 1931 just two days after the City had made its last payment for damages from the previous explosion to St Martin’s Chapel. As was the case in 1929, it started in the Golden Triangle area of Centre Town, this time at the corner of Lewis and Robert Streets. The explosion was accidently ignited by a plumber’s assistant who was investigating the source of a foul odour in the basement of a home. Apparently, a spark from a trowel he was using ignited gas emanating from the sewer.

Replicating in many ways the 1929 disaster, the blast rumbled down the main sewer line blowing up manhole covers in Sandy Hill along Templeton Street, Nelson Street and Somerset Street East, through Strathcona Park, before travelling along the east bank of the Rideau River to John Street in New Edinburgh. As in 1929, twenty-eight manholes covers were sent flying, sixteen of which featured in the earlier disaster. The damage sustained to the sewer system was severe. There were at least four breaks. The 78-inch main sewer on the Eastview (Vanier) side of the Cummings Bridge, which carried much of the sewage from the eastern portions of the city to the outfall at John Street into the Ottawa River, was fractured. Another 54-inch sewer running from Ottawa South along the west bank of the Rideau River was also ruptured near the Strathcona Hospital. With these breaks, sewage backed up into Sandy Hill. To prevent the flooding of homes, the City excavated at two points, one on Somerset Street and the other near the Isolation Hospital, and pumped the sewer water into the Rideau River. In total, more than a mile of sewer was wrecked with damage placed at almost $400,000, roughly ten times that of the earlier 1929 sewer explosion.

Headline, The Ottawa Evening Journal, 29 January 1931

Fortuitously, this time no lives were lost. There were, however, a number of close calls. Twelve-year old Munroe Dingwall of 138 Goulburn Avenue was skiing on Somerset Street East with friends when a manhole cover blew up beside him. The lad was lifted into the air, skis and all, and deposited stunned but unhurt into a snowbank. Poor Miss Pettypiece, who suffered grievous injuries in the 1929 explosions, was on a bus near home when a manhole exploded. She collapsed and had to be treated for shock. A number of children were skating on the Sandy Hill rink on Nelson Street between Somerset East and Templeton Street when gaping holes appeared in the streets around the rink. The children were unharmed and taken to safety.

The City launched two inquiries. The first by consulting engineers Gore, Naismith and Storrie of Toronto concluded that gasoline and illuminating gas were “reasonably probable” causes. Of the two possibilities, the engineers favoured illuminating gas on the grounds that there was little evidence of flames or black smoke emanating from the explosions that would have been characteristic of a gasoline fire. Also, they viewed it as improbable for a perfect mix of gasoline vapour and air to have occurred. But, in the absence of all data and an analysis of sewer air before the explosions, they refrained from given an opinion regarding the source of the responsible gas.

They did, however, make a number of recommendations. First, they recommended that there be a judicial inquiry under oath so that all relevant records and other information pertinent to an inquiry could be obtained. Second, they argued that Ottawa’s method of ventilating sewers was dangerous and obsolete. They recommended the construction of more ventilating shafts, the opening of manhole covers, and the checking of home drains attached to the sewers. Apparently, many were not properly trapped. Other recommendations included the regulation and supervision of establishments using flammable gases or liquids, a regular inspection of sewers every six months, and the construction of sewage treatment plants.

A second committee chaired by Dr Alfred E. MacIntyre, a retired former chief of the Explosives Branch of the Dominion Government, focused on the causes of the blasts. MacIntyre had also consulted on the Campbell Report into the earlier 1929 explosion. He was of the opinion that illuminating gas had been the cause of both explosions. His report concluded that “gas had adventitiously entered the soil, drainpipes, sewer, etc. from defects within the gas distributing system of the Ottawa Gas Company.” Needless to say, the Gas Company came up with the opposite conclusion averring “that gas is the last thing that could be considered in connection with the recent sewer explosions.”

MacIntyre was pretty damming of the City as well. His report said the City had made no attempt to investigate the 1929 explosion, and that the investigations of complaints about fouls smells from residents were “neither informative nor satisfactory.” He contended that members of the inspectorial staff “had neither developed their powers of observation nor acquired sufficient qualifications and knowledge to discriminate or determine the actual condition of hazards, nor a conception of fitting methods of relief, conditions largely attributable to lack of instruction and direction.” MacIntyre also criticized the City for improper ventilation of the sewers, a charge to which the City responded by saying that it was not responsible for keeping sewers free of volatile gases that enter the sewers through the negligence of another company.

On release of MacIntyre’s report, the Board of Control suspended Mr W. F. M. Bryce, the engineer responsible for Ottawa’s sewers for negligence in not taking adequate measures to ensure that the sewers were kept free from dangerous gases. Bryce subsequently resigned. Earlier in the year, Mr A.F. Macallum, the Commissioner of Works, had also resigned, having been held responsible for not taking sufficient precautionary measures to avoid a repetition of the 1929 blasts.

At City Hall, the two investigations into the 1931 explosions set the proverbial cat among the municipal pigeons. Amidst a rancorous debate, City Council defeated on a split 11-11 decision a motion supported by Mayor Allen for a judicial inquiry into the explosion as recommended by the consulting engineers from Toronto. A motion for an independent inquiry into the conduct of Mr Bryce, the sewer engineer, was also defeated on a close 11-10 decision. Subsequently, however, the City launched a law suit against the Ottawa Gas Company in the amount of $376,000 for damages resulting from the 1931 blasts. Despite the testimony of roughly 100 witnesses, the evidence provided by the two inquiries into the sewer explosions, and an admission of the Ottawa Gas Company that its pipes and gas mains had not been inspected since they were installed, the Court ruled in favour of the gas company owing to lack of evidence. After losing an appeal, the City paid the court cost of both parties.

Following the inquiries, the City took steps to improve ventilation in the sewers, including the establishment of another ventilation shaft in Strathcona Park. Measures were also taken to improve the investigation of complaints of sewer smells by residents through the establishment of a complaints bureau. In the end, only Mr Macallum, the former Commissioner of Works, took the fall for the sewer disaster. Roughly eighteen months after the explosion, the Board of Control unanimously re-appointed Mr W. F. M. Bryce to his old job as sewer engineer on the curious and vague grounds that the Board had earlier requested his resignation not because members felt that he “was not fully competent, but because of the nature of the report dealing with the investigation.”