What is Asbestos?
Asbestos is the name given to a group of six naturally occurring silicate minerals which have long, thin fibrous crystals. Each visible fibre is composed of millions of microscopic ‘fibrils’ that can be released into the air by abrasion.
Asbestos fibres are mechanically strong and highly resistant to heat and chemical attack. In addition, because of its fibrous nature, asbestos can be woven into fabrics and used as reinforcement for cement and plastics.
Historically the name is believed to derive from an ancient Greek word meaning ‘inextinguishable’ while others believe that the word’s origin can be traced back to a Latin idiom, Amiantus meaning ‘unpolluted’
Mining of raw asbestos existed more than 4,000 years ago, but large-scale mining did not begin until the end of the 19th century when manufacturers and builders began commercial exploitation of asbestos because of its desirable physical properties.
Asbestos use continued to grow through most of the 20th century with approximately 6 million tonnes of asbestos imported into the UK and annual levels peaking in 1973 at 195,000 tonnes.
It is estimated that over 3000 products made use of the unique properties of asbestos, although some are judged to be more dangerous than others due to the amount of asbestos and the material's friable nature. Sprayed coatings, pipe insulation and Asbestos Insulating Board (AIB) are thought to be the most dangerous due to their high content of asbestos and friable nature.
Despite its use over many years, the dangerous impact of asbestos on health is not a new discovery by any means, even early civilizations such as the Greeks and Romans documented the harmful effects of asbestos.
Greek geographer Strabo noted a ‘sickness of the lungs’ in slaves who extracted the material or those who spun and wove asbestos into fabric. Roman historian Pliny the Elder, wrote of the ‘disease of slaves’ and recorded that slaves who mined asbestos suffered from a sickness of the lungs and died at an early age. He also described the use of a thin membrane from the bladder of a goat or lamb used by slave miners to protect them from inhaling the harmful asbestos fibres.
Awareness and legislation regarding the health hazards of asbestos and its now prohibited status in most countries appears to have lagged unduly, compared to the evidence of the risks.
However, despite theories suggesting a cover-up, it is more likely that the issue was one of hindsight.
Why is asbestos dangerous?
Inhalation of asbestos fibres can cause a number of fatal or serious respiratory conditions.
Asbestos is a category 1 human carcinogen.
It is estimated that the number of people in the United Kingdom suffering from past exposure to asbestos is still increasing and currently the cause of circa 5000 deaths per year.
This figure is significantly higher than the number of people who die in the UK from road traffic accidents.
This large number of deaths mostly reflects past heavy exposures from the manufacturing and installation of asbestos products. However, many asbestos containing materials (ACMs) still remain in buildings and must be managed to reduce the exposure and risk.
There is an increased risk associated with exposure to amphibole asbestos fibres (amosite, crocidolite) in comparison with chrysotile asbestos.
‘Asbestos kills more people in the UK than any other single work-related source’
The risk of developing an asbestos-related disease is dependent on exposure. Working on or near damaged asbestos containing materials or breathing in high levels of asbestos fibres will increase the chance of getting an asbestos related disease. The largest group of workers at risk from asbestos related diseases are those in the building and maintenance trades.
A safe threshold of exposure has not been identified. As the diseases can take several decades to develop, there is no immediate apparent damage or ill effects.
There are four main diseases caused by asbestos fibre inhalation:
A cancer which affects the lining of the lungs (pleura) and the lining surrounding the lower digestive tract (peritoneum). It is almost exclusively related to asbestos exposure and by the time it is diagnosed, it is almost always fatal. Mesothelioma has a long latency period from first exposure to the onset of disease, on average 30-40 years.
Asbestos-related lung cancer is a malignant tumour of the lungs’ air passages, it is estimated that there is approximately one lung cancer for every mesothelioma death. The time between exposure to asbestos and the occurrence of lung cancer is on average 20-30 years.
It should be noted that there is a synergistic effect between smoking and asbestos exposure, which significantly increases the risk of developing lung cancer.
Asbestosis is a serious scarring condition of the lung that normally occurs after heavy exposure to asbestos over many years. This condition can cause progressive shortness of breath and in severe cases can be fatal.
Pleural thickening is generally a problem that happens after heavy asbestos exposure. The lining of the lung (pleura) thickens and swells. If this gets worse, the lung itself can be squeezed, and can cause shortness of breath and discomfort in the chest.
A Brief History of Asbestos
Asbestos cloth used to wrap embalmed Egyptian pharaohs
Asbestos fibres used to strengthen clay cooking pots and provide greater heat resistance
Asbestos used in cremation cloths to prevent ashes being mixed with those of the fire
Woven mats, lamp wicks and table cloths that could be cleaned by throwing into the fire
Asbestos paper and boards produced in Italy
Crocidolite Asbestos discovered in South Africa
First patent is issued for use of asbestos as an insulation material for steam engines
Asbestos clothing worn by fire fighters in France
Founding of Asbestos companies in England, Scotland, Germany, Canada and Russia.
Chrysotile asbestos discovered in Quebec, Canada
First bronchial problems identified in asbestos workers
Chief Inspector of Factories in the UK reported to Parliament in his Annual Report on:
‘The evil effects of asbestos dust’
The sharp, glass like nature of the particles. when allowed to remain suspended in the air, have been found to be injurious, as might have been expected’
First documented asbestos related death
Amosite asbestos discovered in South Africa
Global asbestos production exceeds 100,000 tons
First published case of death due to Asbestosis - Textile Worker Nellie Kershaw
Asbestos Cement Products available
The first asbestos industry regulations were passed in the UK
Asbestos used as fire-proof suits and parachute flares
Post war construction places heavy dependence on asbestos building products
The Kent cigarette company uses crocidolite asbestos in their ‘micronite’ filters
Voluntary ban on the import of Crocidolite Asbestos in the UK
Court of Appeal confirms the first successful personal injury claim from asbestos exposure
Global asbestos production rises to more than 4,000,000 tons annually.
UK imports 195,000 tons
Voluntary ban on the import of Amosite Asbestos in the UK
Health & Safety Executive in UK requires all contractors working with asbestos to be licensed
Import and use of Crocidolite (Blue) and Amosite (Brown) asbestos banned in the UK
The first Control of Asbestos at Work Regulations introduced in the UK
Supply and use of Chrysotile (White) asbestos banned in the UK
Professor Julian Peto (et al) publishes a report showing asbestos deaths are increasing at an alarming rate
All asbestos use banned in the UK.
Control of Asbestos at Work Regulations amended to include Regulation 4 (Duty to Manage)
Chrysotile asbestos banned throughout European Union
Introduction of Control of Asbestos Regulations
Mesothelioma Act passed in the UK.
Asbestos is banned in more than 50 countries
Global production around 2,000,000 tons annually