HOW DANGEROUS IS NATURAL GAS?
Three quarters of a million Canadians use it. Another million are potential customers. But headlined explosions have made many fearful about using this great power source. To what extent are their fears justified? Is it safe to bring this new fuel into your home?
Every day a relatively unknown and highly explosive fuel is pumped through pipes below the streets of five hundred municipalities between Vancouver and Montreal.
Factories, warehouses, office blocks, stores, schools and homes use it for power, heating, cooking, refrigeration, air-conditioning and other purposes. But if it escapes, it has the strength to blow every village, town and city that stands above its course into a mount of corpse-strewn rubble. This fuel—natural gas—has three times the heat and twice the volatility of the manufactured gas it has replaced in every province west of the Maritimes.
Alive to its dangers, the provinces of British Columbia, Alberta,
Saskatchewan, Manitoba and Quebec have introduced stringent laws regulating the safety of natural-gas distribution. In Ontario, where the overwhelming majority of accidents have occurred, a gas safety bill is being drafted for the legislature by the provincial fuel board. But until it is passed, safety precautions are largely in the hands of the gas companies.
During the past five years fifteen Ontario people have been burned or blasted to death by natural gas and more than a hundred others have been injured. Damage from natural-gas fires and explosions has amounted to six million dollars. Ontario Fire Marshal W. J. Scott has described natural gas as ‘'the caged tiger."
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HOW DANGEROUS IS NATURAL GAS? continued
“Accidents can never be entirely eliminated, but we're proud of our
One of the latest of a long series of accidents in which Ontario homes have been blow n to pieces occurred late last month. Two gas company employees repairing a leak in the basement of an Oakville home accidentally released a large volume of natural gas. They rushed upstairs shouting to the family: “For God’s sake get out.” A mother and three children escaped a few seconds before a spark from the furnace touched off a detonation that reduced the property to a heap of debris.
The Ontario disasters, and the recriminations that followed them, have been so widely publicized that three quarters of a million customers in Canada, and a million potential customers, find themselves in a dilemma. They are asking, "Is it safe to use natural gas?”
For more than forty years, natural gas has been found and used in small quantities in southwestern Ontario without any remarkable effect on the accident rate. It was not until 1954, when large
supplies were first piped into the province, that spectacular and often fatal detonations began to occur w ith alarming frequency. The first natural gas from outside Ontario was American. Last October, when the Trans-Canada Pipe Line Company’s system was completed, the American supply gave way to natural gas from Alberta. Both these newer gases have inflicted a severe loss of life and money on Ontario.
Of six million dollars total damage, five million dollars’ worth was caused by an explosion last October in the basement of a two-story building in downtown Ottawa. The property was blowm to fragments. The adjoining buildings, a movie theatre and an auto showroom, were wrecked. Every window in an eight-story office building half a block away was shattered. A janitor died of third-degree burns and even though the accident happened early on a Saturday morning, thirtyeight passers-by were injured.
Serious explosions have also occurred in Calgary. Winnipeg and Montreal, but the biggest incidence of accidents has been in the area bounded by the Ontario cities of London, Hamilton. Toronto, Ottawa and Cornwall.
Despite the Ontario accidents, natural gas ranks today as Canada’s fastest-growing source of fuel. Eighty-eight percent of the natural gas now' used in Canada is drawn from w'ells in British Columbia and Alberta. Since the end of the war the number of customers has multiplied from two hundred and fifty thousand to nearly eight hundred thousand. The Canadian Gas Association, an organization of distributing companies, is confident that at least a million more customers eventually will buy it.
This optimism is based on predictions of the recent Royal Commission on Canada’s Economic Prospects, which estimates that natural gas will develop most quickly as an industrial fuel and
most noticeably at the expense of coal and wood. By 1980, the commission says, the contribution ot natural gas to total energy consumption will rise trom its present figure of six percent to twenty-five percent.
Only oil and hydro-electric power, says the commission, will hold their own against natural gas. The consumption of oil will remain steady until 1980 at about forty-five percent of the total. The consumption ot hydro-electric power will rise trom ten to eleven percent of the total. Nuclear fission, not yet a power source in Canada, will, by 1980, provide two percent of our energy.
Even though the technical and financial experts ot the commission are certain that nothing can stop natural gas from becoming Canada’s number-two fuel, the industry today is encountering stiff resistance to sales, largely because of the Ontario accidents.
John Semans, Manitoba chairman of the Cana-
dian Plumbers and Mechanical Contractors Association, says: “Once potential customers have got it fixed in their minds that natural gas is dangerous, you can't sell 'em. They say they’ve heard about the accidents in the east and that they wouldn't have it in the house for love nor money.” The Ontario accidents have also aroused a clamor of criticism. Last February John J. Wintermeyer, Liberal opposition leader in the Ontario Legislature, accused Leslie Frost's Conservative government of “toying with its responsibilities,” in its failure to regulate the safety of natural-gas distribution. Last November, after the death of a mother and child in a Palermo, Ont., naturalgas explosion, Reeve Alex McPherson of nearby West Flamboro said: “The gas companies are getting away with murder.”
But Oakah L. Jones, general manager of Consumers' Gas Company of Toronto, one of the oldest and biggest in the business, claims the ratio of accidents to gas consumers is no higher than the ratio of accidents to consumers of other fuels. “We are being persecuted for political reasons,” he says, “by newspapers and politicians opposed to the present provincial government, and for commercial reasons by other fuel interests.” Criticisms of the Ontario distributors by technicians, politicians, editorial writers and vendors of other fuels are based largely on the fact that some natural-gas companies are using — as an economy measure—many miles of pipes that were laid in the days of Victoria, Edward VII and George V. These were installed to carry the now almost obsolete manufactured gas to old-fashioned mantle lamps, stoves and laundry boilers. Most critics see significance in the fact that most of the accidents have occurred in communities where many properties are receiving natural gas through pipes once used for manufactured gas.
Most old manufactured-gas pipes are made of cast iron. Usually they arc jointed by the belland-spigot method, that is by pushing the smallcalibre end of one section of pipe into the bigcalibre end of another, and sealing the union with packing. New pipes, laid especially for natural gas. are nearly all steel, with welded joints. Gradually the cast-iron pipes are being replaced by
steel pipes, but in the opinion of many experts the cast-iron pipes should never have been used at all.
M. S. Hurst, Ontario deputy fire marshal, says: “Ninety percent of the natural-gas accidents I’ve investigated stemmed from the use of old manufactured-gas pipes. There is widespread and dangerous ignorance of the radical differences between natural gas and manufactured gas.”
Chemically the two are quite different. Manufactured gas, usually made from coal, is compounded largely of carbon monoxide and hydrogen. The main constituents of natural gas, which is an effluvium from fossilized fish, are methane and ethane.
Nor is there any similarity in their heat content, which is gauged by the British Thermal Unit, a standard measure. Manufactured gas contains about four hundred and fifty BTUs per cubic foot and natural gas contains about fifteen hundred. In combustion, therefore, natural gas is three times hotter than manufactured gas.
Both gases may be exploded by a spark or naked flame. Manufactured gas becomes explosive when it is mixed in a proportion of five parts to one part of air. When it reaches a proportion of fifteen parts to one part of air the mixture is too rich to detonate and merely burns. Natural gas explodes initially in a mixture with air of three parts to one. It remains in an explosive state until it reaches a density of thirty parts to one of air. Thus natural gas is almost twice as susceptible to explosion as manufactured gas. “Furthermore,” says Dr. R. R. McLaughlin, head of the University of Toronto Department of Chemical Engineering, "the detonation of natural gas is very much sharper than that of manufactured gas.”
Manufactured gas is humid and in passing through bell-and-spigot joints of cast-iron pipes its moisture tends to swell and seal the packing. Natural gas is dry, and although gas companies add humidity it still tends to desiccate the packing in cast-iron pipe joints and so leak more readily than manufactured gas.
Manufactured gas has a strong odor and can usually be detected by smell. Natural gas is odorless. Even though the gas continued on page 61
Two views on the dangers of natural gas
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How dangerous is natural gas?
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“A tiny, quarter-inch pilot light suddenly became
six-foot tongue of roaring flame"
companies add an artificial odor this can he filtered out by some kinds of earth, whereupon its escape may go undetected.
Manufactured gas, made at the local gas works and transmitted over short distances, is usually pumped through pipes at a pressure of about four ounces per square inch. Natural gas, which is transmitted in Canada over two thousand miles, is pumped through large-diameter steel pipes at pressures of up to one hundred and fifty pounds per square inch. Normally these high pressures are reduced progressively by valves as the gas approaches the service pipes leading to the property of individual consumers. But if one or more of the valves fail, natural gas can enter service pipes at lethal pressures.
According to Allen Johnson, a U. S. consulting engineer in fuels and combustion, a recent explosion in Brighton. N.Y., resulted from the uncontrolled surge of high-pressure gas into low-pressure pipes. The disaster was touched off when a tiny quarter-inch-long pilot light in a domestic heating furnace suddenly was fed by a gas pressure of twentyfive pounds per square inch and became a six-foot tongue of roaring flame. Three children were killed and forty-four houses were blown apart.
In Canada there is no record of a comparable break-through of high-pressure gas into low-pressure systems. But some experts believe that in older districts an increasing demand for supplies of natural gas has led to the imposition on cast-iron mains and service pipes of pressures they were never built to withstand.
“There can be no doubt,” says Deputy Fire Marshal Hurst, “that some cast-iron pipes arc under great strain. On top of rising pressures in old cast-iron mains there is the problem of increased traffic. Streets which were built in the days of horse-drawn vehicles are now carrying a heavy daily flow of cars and trucks. Below ground the old cast-iron gas mains, which arc less flexible than welded-joint steel mains, get dislocated or cracked or fractured, and dangerous leaks begin."
Even the weather represents a threat io the security of natural-gas pipes. This was evident early in March when Consumers' Gas took half-page advertisements in Toronto’s three daily newspapers under the heading:
PUBLIC NOTICE OF VITAL IMPORTANCE TO YOU.
The advertisement said in part: The severe winter weather experienced this past year has created a deeper frost level than normal. When the frost "comes out,” as milder temperatures prevail, ground movement will be greater than in other years. Under these abnormal conditions the possibility of natural-gas leakage is increased. The Gas Company therefore requests the assistance of all the citizens in the community in guarding against gas leaks that might otherwise go unnoticed.
The advertisement asked citizens to report:
(1) Any noticeable bubbling in pools of water on the ground and
(2) Any odor which has no readily apparent cause, either in buildings or out of doors;
(3) Any indication that your furnace, regardless of fuel, does not appear to be operating as it should.
Another threat arising from the use of manufactured-gas mains to distribute
natural gas is the existence, in the basements of thousands of older properties, of capped gas pipes. These pipes were capped when the property owners abandoned manufactured gas for electricity. In the meantime, behind the cap, natural
gas has taken the place of manufactured gas often without the knowledge of the present property owners. If the cap rusts away, or if it is removed experimentally, accidentally, or mischievously, the building is in peril. It requires only this combination of events to blow that building sky high—a leak of natural gas to a density of between three parts and thirty parts to one part of air and a coincidental spark from the motor of an electric furnace.
Some people don’t understand the danger. Last February a Toronto woman
appeared in court and pleaded guilty to theft. She had removed the cap from the old manufactured-gas pipe in her basement and substituted an ordinary water tap. From the tap she led unmetered natural gas to her furnace by a length of rubber hose. Her Rube Goldbergish rig was so leaky that it exposed the entire neighborhood to the risk of being blown up.
In Toronto alone there are between forty and fifty thousand properties equipped with old, capped manufactured-gas pipes. Deputy Fire Marshal Hurst says:
“The possibility that many people are monkeying around with the caps to obtain free natural gas is disturbing.”
A missing cap was responsible for the explosion at the Leduc Hotel, Leduc, Alta., in 1950. A spark from an electric furnace motor touched off the leak. Ten people died in the blazing debris and ten more were seriously injured.
The spectacular Ottawa explosion last October was caused by the removal of a cap from a pipe that once was used to supply the building with manufactured gas. Nobody knows who removed the
cap or when or why. Experts discovered later that for years before the explosion the pipe had been blocked by an accumulation of moist silt. When natural gas replaced manufactured gas its dryness began to turn the moist silt to dust and to push the dust aside.
On the morning of October 25, natural gas was leaking into the basement. Investigations showed that the gas reached a density of ten parts to one part of air. This is the optimum explosive mixture of natural gas, a mixture at which it can be more violent than dynamite. The janitor went down into the basement, switched on an electric light, and created a spark.
The blast demolished the two-story building. The force of the explosion was so great that it hurled two manhole covers—each weighing one hundred and fifty pounds—from their seatings in the street. One cover sailed through a topfloor window in an eight-story building a hundred yards away, and the other landed on the roof of the same property. Every window of this building was blown out. Had the accident happened during working hours, hundreds of civil servants in the eight-story building might have been killed or injured.
Fifty serious natural-gas accidents in Canada over the last ten years have revealed a pattern of causes. The pattern breaks down into four divisions:
(1) Leaks from missing or defective caps on disused manufactured-gas pipes;
(2) Leaks inside buildings from defective pipes or appliances;
(3) Leaks outside buildings caused by natural gas drying out the packing in (he bell-and-spigot joints of cast-iron pipes;
(4) Leaks outside buildings caused by the vibration of traffic, which can fracture both cast-iron and steel pipes.
The most tragic gas explosion originating in steel pipe was that which killed Mrs. Roy Skinner and her son Gregory in their bungalow near Palermo, Ont., in November. Mrs. Skinner's husband was seriously injured. Ironically, the Skinners did not use natural gas themselves.
Heavy traffic is believed to have cracked a valve in the new steel pipe that ran under the highway past the Skinners' home. Escaping at high pressure, the gas took the line of least resistance— along the outside of its own pipe where the earth, through the disturbance of excavation, was less tightly packed. It reached another underground pipe—the Skinners’ sewer pipe. It changed course and followed the outside of the Skinners' sewer pipe into their basement via the tiny crevices surrounding the sewer's point of entry. In the basement the gas accumulated until it was touched off by a spark from a furnace motor.
Natural gas leaking from a distant point in a pipe and seeping into a basement caused a big explosion in Montreal last January. A two-story building containing a restaurant and three dwellings was demolished. Fifteen people, including seven children, were seriously injured. The same sort of distant leak and seepage caused an explosion in a suburban Toronto bank in 1956. A bank employee went down into the basement vault, lit a cigarette and ignited natural gas.
Commenting on these explosions an expert on the staff of the Michigan Public Services Commission said recently: “Heavy traffic vibration has become a dangerous source of natural-gas accidents, especially when such traffic passes over old cast-iron-pipe systems.”
Lack of confidence in cast-iron pipes
“The gas was leaking in through a sewer pipe. Several hours later, the owner lit a cigarette . .
has also been demonstrated by at least one Canadian company. When Nelson, B.C., converted from manufactured to natural gas Inland Natural Gas Company, the distributing agent, tore up all the cast-iron pipes and replaced them with a new steel network.
Leaks are a continual bugbear in castiron-pipe systems. Many engineers believe that the water and oil which gas companies add to the gas to keep the packing in bell-and-spigot joints moist and tight don't always work. An indication that gas companies themselves are worried about this problem was given by Norman Mork, chief gas engineer of the New York State Public Services Commission, in a recent speech in Toronto. Mork said that in his own state gas companies were engaged “in urgent experiments” for sealing old cast-iron mains by blowing through them liquid plastic and rubber compounds which, they hoped, would form a protective film around the insides of the pipes.
There is also some evidence to suggest that the odor added to natural gas by distributors as a safety precaution is not always adequate/ Allen J. Johnson, a U. S. consulting engineer, told a recent convention of the Oil Heat Institute of New York City: “Added odors tend to diminish with distance and to filter out as leaking gas passes through moist earth. Furthermore, dust and pipe scale in dry distribution systems also filter out the odorants. Thus od^rization. while essential, cannot be depended on as an infallible warning of leakage.”
Johnson's criticism was based on cases like one some years ago in Calgary. Sub-zero weather cracked a cast-iron gas valve below a street. Nearby consumers complained to Calgary's Canadian Western Natural Gas Company Ltd. about reduced pressure in their appliances. In looking for the leak, employees of the gas company entered a house on Kensington Road. They detected no trace of gas. But gas was leaking into the house along a sewer pipe. Several hours after the gas-company employees left, the owner lit a cigarette. The detonation wrecked the house and killed two occupants. Later investigations showed that the odor in the gas had been filtered out during its passage through a gravel bed.
In November. 1957. twenty union members meeting in the Carpenters’ Hall, New Westminster, B.C., were overcome by lack of oxygen. Interviewed later in hospital the men said they were unaware that anything was wrong until their chairman collapsed while making a speech. “We got up to help him,” said one man, “and half of us collapsed too.”
The suffocation was caused by a leak of natural gas from a furnace. Failure
M ACCRA N’S
to detect the leak was attributed to the absence of odor.
Cases of this kind point up the one characteristic in which natural gas is safer than manufactured gas. Natural gas is non-toxic. It can suffocate a person only by displacing air to such an extent that vital oxygen is dispersed. Manufactured gas, even in small quantities, can asphyxiate a person by the
presence of its lethal carbon monoxide.
So it is not so easy to commit suicide by breathing natural gas as it is by breathing manufactured gas. Arthur R. Elliott, a native of Muncie, Ind.. who is manager of the Greater Winnipeg Gas Company, recalls a woman who tried to end her life with natural gas. Confusing its properties with those of manufactured gas she closed the doors and
windows of her home, turned on the natural-gas cocks and lay down on a chesterfield to await death. After an hour or so of waiting in vain she became impatient and decided to have a last cigarette. It was only then that she achieved her purpose. She Hicked her lighter. The explosion blew out the walls and raised the roof. Nobody would have known how it happened if she had not
lived long enough in hospital to tell the story.
Natural-gas companies defend themselves stoutly against charges of sacrificing public safety in the interests of economy. W. L. Landon, chief engineer of the Consumers’ Gas Company of Toronto, says: “The cast-iron mains arc perfectly safe. We are testing them all the time. A few weeks ago we took up a length of cast-iron pipe that had been in the ground for ninety years. It was in perfect shape so we put it back. On the other hand we’ve put in sections of castiron pipe that have lasted for only four or five years. Their life depends upon the nature of the soil they’re lying in. In some soils they’re safer than steel pipes. It is ridiculous to condemn all cast-iron pipes on the basis of a few explosions.”
Landon says that the odor gas companies add to natural gas is unmistakable and leads to the rapid detection of the overwhelming majority of leaks. He claims the humidity added to keep the packing in joints moist is also effective. “In our own system,” he says, “which is the biggest in Canada, we’ve not had a single case of a leak due to drying out of packing.”
No comparisons are available in Canada between the fatality and damage rate of natural gas and the fatality and damage rate of other fuels. In the United States, where eight million out of forty million householders use natural gas, the National Fire Protection Association publishes an annual analysis of building losses by fire and explosion. The latest figures show that out of 843,000 fires and explosions, twenty-two thousand were caused by natural gas. As a fire hazard natural gas rated tenth after smoking and matches; defective electrical services; misuse of inflammable liquids; children with matches; lightning; spontaneous ignition; oil-fired equipment; overheated chimney flues; and unexplained ignition of rubbish.
No particular fear of natural gas is evinced by Canadian insurance companies. One insurance broker says: “There are no special premiums on properties equipped with natural gas.” Winnipeg Fire Chief Dave Dunnett says, “We’ve had no special trouble with natural gas outside the odd leak and these have all been detected before harm has been done.”
Most gas companies ascribe the fear of natural gas to the publicity given to explosions. Harold J. Robbins, administrative assistant to the president of Calgary's Canadian Western Natural Gas Company Ltd., says: “If a householder loads his electrical circuits beyond their capacity and a fire results the newspapers report it as an unfortunate occurrence. If a fire is caused through the careless handling of natural gas it is usually presented as a shocking example of the way in which citizens are exposed to modern dangers.”
D. Cass-Beggs, general manager of the Saskatchewan Power Corporation, a provincially owned company which distributes natural gas, is also critical of the way newspapers report gas accidents. He says: “The term ‘gas’ is used loosely. A press story may speak of ‘a gas explosion,’ referring to a gasoline explosion and the public wrongly infers the cause is natural gas. Similarly a carbon-monoxide death may be referred to as gas poisoning.’ The readers get distorted ideas of the dangers of natural gas.”
At a recent convention of the Ontario Weekly Newspapers’ Association in Toronto, Oakah L. Jones, vice-president and general manager of the Consumers’ Gas
Company of Toronto, pleaded for the presentation of gas accidents in “a proper perspective.” He held up a booklet, of anonymous origin, which has had widespread circulation in Ontario. It was filled with photographs of gas accidents, reproductions of newspaper editorials and articles by engineers emphasizing the dangers of natural gas. Jones said: “I suspect the thing has been printed by rival fuel interests.”
In a long list of alleged natural - gas accidents the booklet includes an incident at Peterborough, Ont., on Jan. 4, 1957, when “a hundred feet of sidewalk were ripped up by gas blast.” Peterborough is one of the few cities in Ontario which is not yet served by natural gas.
Jones says: “The Toronto Daily Star is one of our worst enemies. For years it has wanted to see gas distribution handed over to provincial authorities. So whenever we have an accident, the Star gives it big headlines.”
He adds that he is proud of his company’s safety record and of the measures used to maintain it. Once a month crews go down into gas-, electrical-, telephone-, sewerand water-system manholes with apparatus capable of detecting the presence of gas in the atmosphere. Once every three months a gas-detector survey is made of all basements in business districts. Once a year a leak survey is made with detectors of the entire distribution system and all leaks, no matter how infinitesimal, are sealed. Special teams of employees are constantly at work traveling along the course of gas
mains and looking for wilting trees, bushes, llowers and grass, which betray leaks.
“No gas company can honestly promise to eliminate entirely explosions or other accidents,” says Jones, “because no kind of accident can be eliminated so long as human and material elements are involved. But we recognize fully outobligations and meet all standards of workmanship efficiently.”
Most Canadian gas companies base their safety precautions on two codes. Their transmission pipes are laid according to the American Standards Association Code B31, sponsored by the American Society of Mechanical Engineers. Their appliances arc installed and maintained under the Canadian Standards Association Code BÍ49. These, or similar codes, have been made law in British Columbia, Alberta, Saskatchewan, Manitoba and Quebec provinces in which natural-gas accidents can be counted on the fingers of one hand.
In Ontario, where most of the accidents have occurred, there is still no legislation which pins responsibility for natural-gas safety on any particular individual or organization. After the Ottawa explosion municipal engineers denied that it was their job to police the pipes for leaks.
The Ontario Fuel Board, a provincialgovernment body, was set up in 1954 to ensure that natural - gas companies observe the codes of the American and Canadian Standards Associations. Its officers inspect blueprints and equipment and reject them if necessary. But the board does not have power to prosecute the natural-gas companies for failure to maintain standards. “We are not responsible for checking the pipes ourselves,” says the board's chairman, A. R. Crozier. "We haven't* the staff to do it.”
At the moment the Ontario Fuel Board is drafting a natural-gas safety bill for submission to the Ontario Legislature. If this becomes law the natural-gas companies will still be responsible for patrolling their own lines but will be liable to prosecution for breaches of the bill’s requirements.
These requirements, according to Crozier, will be much the same as those laid down in the American and Canadian Standards Associations’ codes. “In drawing up the bill,” says Crozier, "we are really cribbing from the two codes and substituting the word ‘shall' for the word 'should.' In other words we are putting teeth into the codes and providing penalties for breaches of them.”
Another Ontario government body, the Ontario Research Foundation, is meanwhile experimenting on two possible safety devices: an automatic naturalgas detector and alarm which could be produced cheaply enough for installation in every home; and an eye irritant which could be pumped into natural gas to supplement odor as a danger signal.
Comprehensive though these plans are they will not satisfy the coroner's jury that investigated the death at Palermo of Mrs. Roy Skinner and her child. In laying the blame for the accident flatly upon the United Suburban Gas Company Ltd. of Hamilton, and the Gas Machinery Company (Canada) Ltd., the jury recommended the appointment of a provincial commission to approve or reject all natural-gas-pipe development plans and to supervise the inspection of all mains and appliances for safety. The jury added a rider to the effect the provincial government should carry out immediately an inspection of all naturalgas installations “even though this means laying open every mile of pipeline in the province.” ★