November 2011

Historical Metallurgy

History of asbestos

By F. Habashi, Laval University, Quebec City, Canada

Below: Crushing room at Johnson Mine in Quebec (1900). The girls are using hammers to crush the ore.

Since ancient times, asbestos has been used as a fireproofing material. In the first century AD, Strabo, a geographer, identified the first Greek asbestos quarry on the Island of Evvoia, where fibrous stone threads were being combed and spun like wool in the process of making cloth-like products. Strabo wrote: “When these are soiled, they are thrown into fire and cleansed, just as linens are cleansed by washing.” The word asbestos comes from the Greek word meaning “inextinguishable.” The Romans, however, called asbestos “amiantus” (meaning unpolluted), reflecting its easy-to-clean property; the name is the root of the French word “amiante” used today. The first century historian Pliny the Elder also wrote about asbestos being “quite indestructible by fire.”

In 1876, asbestos was discovered in the township of Thetford, Quebec. The tools used to mine the mineral were simple; however, by 1895, mechanization of the process began. This development marked the beginning of a period of unprecedented growth.

The growing railroad industry was among the first to make extensive use of asbestos and asbestos-containing products. The demand for the product increased as railroad engineers began to use asbestos materials to line refrigeration units, boxcars and cabooses; it was especially useful for insulating pipes, boilers and fireboxes in the steam locomotives of that era.

Other industries as well made extensive use of asbestos materials: shipping; automotive (used in brake pads and shoes and in clutch plates); elevators (used in brakes); and industrial construction, which was by far the largest consumer, as it was used as wall insulation, for floor and ceiling tiles, and in exterior siding and roofing.

At the turn of the 20th century, researchers began to notice that a large number of lung problems and deaths occurred in asbestos mining towns. In 1917-1918, several studies indicated that asbestos workers were dying at a young age. In 1924, a woman who had been working with asbestos since the age of 13, died at 33 from what an English doctor called “asbestosis.” Her death led to a study on asbestos workers in England. Evidence showed that 25 per cent of these workers suffered from an asbestos-related lung disease.

In 1931, laws were passed to increase ventilation in areas where people were in contact with the material. Throughout the 1930s, major medical journals began to publish articles that linked asbestos to cancer. Another negative aspect was the amount of waste produced from asbestos mining: about 30 tonnes of tailings were discarded per tonne of asbestos produced.

Despite its known affects on health and the environment, the use of asbestos was at its highest from the 1940s to 1970s. The warnings and regulations that came about in the 1970s and beyond put an end to most of the material’s production, even though the industry had greatly improved its efforts in improving ventilation and dust control. Asbestos was now being recovered from the crushed and ground rock by aspiration, and the air-tight building housing the equipment was under slight pressure to ensure that no fibers were released into the workplace. This was accomplished by recirculating the clean air sucked in by fans at the top of a building through air-pressurized rooms.

Asbestos strike in Quebec

At midnight on February 14, 1949, miners walked off the job at four asbestos mines near Thetford Mines and Asbestos in Quebec. The union demanded that asbestos dust be eliminated both inside and outside of the mill; as well, it demanded a wage increase and a social security fund to be administered by the union. The demands were rejected.

Quebec Premier Maurice Duplessis sided with the companies, due to his hostility to all forms of socialism. The provincial government sent police to protect the mines. Duplessis’ Union Nationale party had long been closely allied to the Catholic Church, but in this case, the church supported the workers. The population and media of Quebec were sympathetic to the strikers. Pierre Elliott Trudeau, future Canadian Prime Minister and then-journalist, also covered the strike in a sympathetic manner.

Six weeks into the strike, Johns Manville hired strikebreakers to keep the mines open. In response, the strike turned violent as the 5,000 strikers fought back and destroyed the property. More police were sent to protect the strikebreakers and hundreds of miners were arrested. Some of the incidents included a dynamite explosion that destroyed part of a railroad track that led into the Johns Manville property and the overturning of a company jeep, injuring a passenger. On March 5, Archbishop Joseph Charbonneau delivered a fiercely pro-union speech asking all Catholics for donations to help the strikers. Premier Duplessis asked the church to transfer the archbishop because of his pro-union stance, but his request was refused.

Archbishop Maurice Roy of Quebec City served as mediator. In June, workers agreed to return to work with few gains. In the long term, both conditions and wages of the workers considerably improved. Trudeau edited The Asbestos Strike, a book portraying the strike as a violent announcement that a new era had begun.

Nationalization of the asbestos industry in Quebec

As Minister of Natural Resources in 1976, Yves Bérubé (1940-1993) presided over the creation of a state corporation for research, prospection and promotion of asbestos. In 1978, the National Society of Asbestos, located in Sherbrooke, Quebec, was established as an organization of the Quebec government. The society had a research department directed by Jean Marc Lalancette, a chemistry professor at the University of Sherbrooke, who developed chrysotile phosphate by reacting chrysotile asbestos with gaseous phosphorus oxychloride (POCl3), which, he claimed, reduced its toxicity. Researchers at Laval University also demonstrated that the toxicity of asbestos could be reduced by dyeing the fibers with certain organic dyes.

In 1980, the Quebec government decided to nationalize the industry. However, a promotional campaign soon followed, claiming that asbestos was a carcinogenic mineral. This resulted in a drastic decrease in demand and production.

Asbestos Institute

The Asbestos Institute was created in 1984 in Montreal as a non-profit organization to promote the adoption and application of appropriate prevention and control measures, regulations, standards, work practices and techniques for the safe use of asbestos. It took part in international conferences offering relevant documentation, advice, or technical, medical and scientific training to asbestos producers and users.

Banning of asbestos

In 1986, the Environmental Protection Agency in the United States banned the use of asbestos on the grounds that it is a carcinogenic material. The asbestos producers in Canada, however, sued the agency and, in 1991, the Court of Appeals ruled against the ban citing insufficient proof.

Magnola project

In 1996, the magnesium pilot plant at CEZinc in Valleyfield, Quebec, was recovering magnesium from asbestos tailings (which contained 24 per cent magnesium). In 1997, Noranda Inc. approved construction of the $730 million Magnola magnesium plant in Danville, Quebec, to produce magnesium metal from this resource. Construction of the plant began in the spring of 1998 and it entered production in late 2001. The extraction process involved hydrochloric acid leaching, brine purification and drying to produce granular magnesium chloride, which is melted and electrolyzed to produce metallic magnesium. The metallic magnesium is then tapped and cast in ingots. However, due to a depressed economy and the low cost of production in China, the plant was shut down in 2003.


When the toxicity issue surrounding asbestos surfaced, the industry took steps to improve working conditions by introducing massive ventilation and air filtration equipment. Regardless, the public’s negative perception of this material still prevails and this has resulted in a greatly decreased demand for related products.

Suggested Readings
Habashi, F. (2010). Mining and Civilization. An Illustrated History. Québec City: Métallurgie Extractive Québec, 510 p. Available at: Laval University Bookstore (
Habashi, F. (2011). Researches on Asbestos. Québec City: Métallurgie Extractive Québec, 115 p. Available at: Laval University Bookstore (
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