Asbestos and its use over the centuries
The history of asbestos use by human societies around the World, extends back for more than 40 centuries. But knowledge of the potential hazards of asbestos dates back little more than one century.
Asbestos is generally described as a set of six naturally occurring minerals in microscopic fibre form - each fibre containing millions of even more microscopic ‘fibrils.” They are also commonly grouped as blue, brown, white and green asbestos. These fibres, once breathed into the body, are the known cause of fatality-inducing illnesses.
The derivation of the name asbestos, is believed to be from the Greek language, meaning “unquenchable” or “inextinguishable.” Perhaps also ‘indestructible.” It was discovered to be a very resilient and hardy natural substance which found many uses as human ingenuity was applied over centuries.
Early humans recognised the value of the tensile strength and fire resistance via the use of asbestos. As technology advanced in the industrial revolution and into the 19th century, its properties for sound, heat and electrical insultation encouraged wider use.
One of the earliest recorded uses of asbestos was in Finland 4.500 years ago when people strengthened earthenware pots and cooking utensils. Wealthy ancient Persians had a party trick of cleaning a cloth by throwing it into a fire. The debris was burned away and the asbestos-woven cloth remained intact and clean for use again.
Some archaeologists believe that ancients made shrouds of asbestos, burning the bodies of their kings, in order to preserve only their ashes, and prevent them being mixed with those of wood or other combustible materials. Other recorded uses of asbestos were as perpetual wicks for lamps
The large scale asbestos industries began in the mid-19th century. Early attempts at producing asbestos paper and cloth in Italy began in the 1850s. Canadian samples of early industrial asbestos products were displayed in London in 1862, and the first companies were formed in England and Scotland to exploit this resource. Asbestos was first used in the manufacture of yarn, and German industrialist Louis Wertheim adopted this process in his factories in Germany.
Industrial scale mining began in Quebec, Canada, in the 1870’s. The 50 imperial ton output of that country’s mines in 1878 rose to over 10,000 tons in the 1890s, indicating the growth of World demand. For a long time, the world's largest asbestos mine was the Jeffrey mine in the town of Asbestos, Quebec.
But countries such as USA, Russia, Italy, South Africa and other countries were also mining asbestos from the 19th century.
Many uses and products
The use of asbestos became increasingly widespread towards the end of the 19th century, when its diverse applications included fire retardant coatings, concrete, bricks, pipes and fireplace cement, heat, fire, and acid resistant gaskets, pipe insulation, ceiling insulation, fireproof drywall, flooring, roofing, lawn furniture, and drywall joint compound.
By 2011 it was reported that over 50 percent of UK houses still contained asbestos, despite a ban on asbestos products some years earlier.
In New Zealand, the banning of asbestos in construction from the year 2000, means that any buildings erected since then, are probably free of asbestos. But this leaves many thousands still containing the potentially deadly fibres.
By 2015, two million tonnes of asbestos were still mined worldwide.
The danger of asbestos discovered
In 1899, the negative health effects of asbestos were first officially noted at Charing Cross Hospital in London. The first documented death related to asbestos was in 1906; a young man had died from pulmonary fibrosis after a 14 year career in an asbestos textile factory.
By 1902, the Inspector of Factories in Britain, had included asbestos in a list of harmful industrial substances. Similar investigations were conducted in France and Italy in the first decade of the 20th century.
The first diagnosis of “asbestosis” was made in the UK in 1924; Nellie Kershaw was employed in Manchester, from 1917, spinning raw asbestos fibre into yarn. Her death in 1924 led to a formal inquest. A pathology report recorded examination of the lungs which indicated old scarring indicative of a previous, healed, tuberculosis infection, and extensive fibrosis, in which were visible "particles of mineral matter ... of various shapes, but the large majority have sharp angles."
This motivated a Parliamentary inquiry.
By 1930, British authorities were concluding that the development of asbestosis was irrefutably linked to the prolonged inhalation of asbestos dust, and included the first health study of asbestos workers.This study concluded that 66 percent of those employed for 20 years or more suffered from asbestosis.
The report led to the publication of the first Asbestos Industry Regulations in 1931, which came into effect on 1 March 1932.
Approximately 100,000 people in the United States have died, or are terminally ill, from asbestos exposure related to ship building.
In New Zealand, one Government source states that about 170 fatalities a year continue to result from exposure to asbestos.
In Australia, asbestos was widely used in construction and other industries between 1946 and 1980. From the 1970s there was increasing concern about the dangers of asbestos, and its use was phased out. Mining ceased in 1983. The use of asbestos was phased out in 1989 and banned entirely in December 2003.
Recycling and disposal of asbestos
In most developed countries, asbestos is typically disposed of as hazardous waste in landfill sites.
Asbestos can also be recycled by transforming it into harmless silicate glass. A process of thermal decomposition at 1000–1250 °C produces a mixture of non-hazardous silicate phases, and at temperatures above 1250 °C it produces silicate glass.
This enables asbestos-containing waste to be transformed into porcelain stoneware tiles, porous single-fired wall tiles, and ceramic bricks.
So the long term task to remove asbestos from the lives of all New Zealanders, means we don’t need to simply bury the problem somewhere- we can eliminate it by conversion to other safe building materials.