Asbestos is a mineral with long, thin fibrous crystals. The word asbestos is derived from a Greek adjective meaning inextinguishable. The Greeks termed asbestos the miracle mineral because of its soft and pliant properties, as well as its ability to withstand heat. Asbestos is known to have toxicity. The inhalation of toxic asbestos fibres can cause serious illnesses. Because it is so hard to destroy asbestos fibres, the body cannot break them down or remove them once they are lodged in lung or body tissues. They remain in place where they can cause disease. Entry into the body is through inhalation into lower parts of the lung and can lay there for years, or can even work their way into the lining of the lung. Asbestos diseases are caused by inhaling asbestos dust.

The main diseases caused by inhalation of asbestos are:

  • Mesothelioma (cancer of the lining of the chest and lungs)
  • Lung cancer
  • Asbestosis – the scarring of lung tissue

Mesothelioma is a rare form of cancer that most often occurs in the thin membrane lining of the lungs, chest, abdomen, and (rarely) heart. About 200 cases are diagnosed each year. Virtually all cases of mesothelioma are linked with asbestos exposure. Approximately 2% of all miners and textile workers who work with asbestos, and 10% of all workers who were involved in the manufacture of asbestos-containing gas masks, contract mesothelioma. People who work in asbestos mines, asbestos mills and factories, and shipyards that use asbestos, as well as people who manufacture and install asbestos insulation, have an increased risk of mesothelioma. So do people who live with asbestos workers, near asbestos mining areas, near asbestos product factories or near shipyards where use of asbestos has produced large quantities of airborne asbestos fibres.

Lung cancer causes the largest number of deaths related to asbestos exposure. The incidence of lung cancer in people who are directly involved in the mining, milling, manufacturing and use of asbestos and its products is much higher than in the general population. The most common symptoms of lung cancer are coughing and a change in breathing. Other symptoms include shortness of breath, persistent chest pains, hoarseness, and anaemia. People who have been exposed to asbestos and are also exposed to some other carcinogen, such as cigarette smoke, have a significantly greater risk of developing lung cancer than people who have only been exposed to asbestos. One study found that asbestos workers who smoke are about 90 times more likely to develop lung cancer than people who neither smoke nor have been exposed to asbestos.

Asbestosis is a serious, chronic, non-cancerous respiratory disease. Inhaled asbestos fibres aggravate lung tissues, which cause them to scar. Symptoms of asbestosis include shortness of breath and a dry crackling sound in the lungs while inhaling. In its advanced stages the disease may cause cardiac failure. There is no effective treatment for asbestosis; the disease is usually disabling or fatal. The risk of asbestosis is minimal for those who do not work with asbestos; the disease is rarely caused by neighbourhood or family exposure. Those who renovate or demolish buildings that contain asbestos may be at significant risk, depending on the nature of the exposure and precautions taken.

Present statistics from the Health and Safety Executive (HSE) indicate that at least 3,500 people die each year in the UK from mesothelioma and asbestos related lung cancer as a result of past exposure to asbestos, and numbers are predicted to rise to 10,000 a year by 2020. Those infected are mainly builders, plumbers and shipyard workers, but teachers, children and nurses are believed to have been put at risk since asbestos was used in the construction of several schools and hospitals. Families of those who work with asbestos can also be infected if asbestos particles are brought into the home on clothes.

There is usually a substantial delay between the first exposures of asbestos to the first symptoms of any asbestos related disease, varying from between 10 to 60 years and it can typically take up to 40 years for symptoms to show. Although asbestos is a hazardous material it can only pose a risk to health if the asbestos fibres become airborne and are then inhaled. Therefore, most asbestos materials pose little risk unless they are disturbed in some way that allows the fibres to be released into the atmosphere.

However, all forms of asbestos are dangerous and can cause fatal illnesses to which there is no cure, however, blue and brown asbestos products are known to be more dangerous than white asbestos. The main symptoms include shortness of breath on exertion, a persistent cough, chest pain or tightening of the chest, nail abnormalities and thickening of the fingers and toes. There is no cure for asbestos diseases, but, as severity depends on the length of exposure and amount of asbestos dust inhaled, early identification through chest x-ray can prevent further exposure and worsening of conditions.

People who develop mesothelioma have a particularly bad prognosis. Around 75% die within one year of diagnosis. Mesothelioma can take between 20 and 40 years to develop after exposure to asbestos dust. Other cancers related to asbestos include lung cancer (worsened by cigarette smoking) and cancers of the oesophagus, stomach, colon and rectum.