Asbestos: what is it, and why does it matter?

This Q&A provides some basic information on what asbestos is, the diseases asbestos can cause, and who is most affected.

What is asbestos?
Asbestos is a term used to describe a group of naturally occurring minerals with shared characteristics. It is strong, resistant to heat, fire, and chemical and biological degradation.

Asbestos had been used sparsely since Roman times. It’s referred to in Pliny the Elder’s work circa 70AD, both for its curious properties and the poor condition of the enslaved workers who mined it.

It wasn’t until the 1870s, with extensive industrialisation, that the asbestos industry as we know it emerged. Asbestos was thereafter used extensively in thousands of products, including for insulation, cement, and textiles. It was also found in paint, kitchen appliances, and even cigarette filters.

A photo-essay of just some asbestos-containing materials is here.

There are six different types of asbestos, which can be broken down into two categories: amphibole and serpentine.

The amphibole types of asbestos are crocidolite, amosite, tremolite, anthophyllite, and actinolite. Of these, crocidolite (blue asbestos) and amosite (brown asbestos) were mined, and made up approximately 5% of all asbestos that was produced. The remaining 95% of asbestos that has been mined is serpentine asbestos, whose one form is chrysotile (white asbestos).

Blue asbestos is often categorised as being the most toxic form of asbestos. White asbestos is less potent than amphibole asbestos, as amphibole asbestos fibres are sharper and harder for the body to clear, but all forms of asbestos, including white asbestos, are toxic and carcinogenic.

Asbestos can also be found when talc or vermiculite is mined, as they are sometimes found close together in nature. This has led to instances of asbestos in talcum powder and zonolite.

Where is asbestos banned or still used?
The mining of brown and blue asbestos, which took place largely in South Africa and Australia, ended by 1997/98.

Over 65 countries have bans on all forms of asbestos. This includes European Union members, the United Kingdom, Canada, Australia, New Zealand, Saudi Arabia, South Africa, Turkey, Japan, Argentina, Iran, the USA, and South Korea, among others.

White asbestos continues to be mined to this day. The largest miners are Russia, Brazil, China, and Kazakhstan. More than one million tonnes of white asbestos was mined in 2023. India, Indonesia, Thailand, Uzbekistan and Vietnam are some of the largest importers of asbestos.

What illnesses can asbestos cause?
The major asbestos-related diseases are mesothelioma, asbestosis, and lung cancer. It can also cause pleural plaques and pleural thickening. Other cancers, like ovarian cancer, stomach cancer, and larynx cancer, have also been connected to asbestos exposure.

It usually takes at least 10 to 60 years for the symptoms of asbestos diseases to show. This latency period can make identifying asbestos diseases more complex, particularly in countries which have not invested in training healthcare workers to recognise asbestos-related diseases.

Asbestosis and mesothelioma are diseases which require levels of specialist training to detect and can easily be misdiagnosed. The quality of information gathered by countries on asbestos deaths varies enormously.

What is mesothelioma?
Asbestos has been known to cause mesothelioma since 1960. Mesothelioma is a cancer of the mesothelium, a protective lining of some organs. Mesothelioma is most often found in the lining of the lungs (pleural mesothelioma), but it can also be in the stomach (peritoneal mesothelioma), or very rarely, the heart or testes.

Mesothelioma is a terminal cancer with no known cure. Sixty per cent of patients diagnosed with mesothelioma will die within a year of diagnosis. The average age at which people are diagnosed with mesothelioma in the UK is 75; in Australia, it is 77; and in the USA, for pleural mesothelioma, it is 72.

There are incidents of people with mesothelioma below the age of 40 in countries where asbestos has been banned for years, but those cases are very rare.

For more resources on mesothelioma, visit Mesothelioma UK or Asbestos.com.

What is the link between asbestos and lung cancer?
Asbestos has been known to cause lung cancer since the 1940s. But unlike mesothelioma, lung cancer can be harder to connect to asbestos exposure, as there can be other major contributors, including smoking, air pollution, genetics, and radon exposure.

Scientists estimate that for every death from mesothelioma, there are between 0.25 and six lung cancer deaths from asbestos exposure, depending on the location. Exposure to asbestos for cigarette smokers multiplies the risk of developing lung cancer.

What is the link between asbestos and asbestosis?
Asbestosis is a scarring of the lungs, which also has no known cure and can be fatal. Its common symptoms are shortness of breath, coughing, and fatigue.

Asbestosis can be found in people with significant exposure to asbestos. It has been known to be caused by asbestos exposure since the 1920s, though evidence was also found in the 1900s by British Factory Inspectors. This led to the first asbestos regulations in 1931 to control the amount of asbestos dust in certain UK factories.

Asbestosis can be easily misdiagnosed for other conditions, such as tuberculosis or silicosis.

How dangerous is asbestos?
Asbestos fibres, like those pictured above, can be broken down into millions of smaller fibres. Some of these fibres, when inhaled or ingested, can remain in parts of the body and cause diseases.

The likelihood of contracting an asbestos-related disease is strongly correlated with your exposure to asbestos. However, not everyone who is highly exposed to asbestos will have an asbestos-related disease, and not everyone who has an asbestos-related disease was highly exposed to asbestos. Particularly for blue asbestos, even light exposures can lead to mesothelioma. Scientists aren’t certain why asbestos exposure impacts some people more than others.

Many people, particularly in urban centres, are likely to have had negligible exposure to asbestos as it is in the air, albeit in exceedingly low quantities.

Asbestos-related diseases are the leading occupational killer in many countries, particularly in Europe. An estimated 200,000 people die annually from asbestos exposure, according to the World Health Organisation. Since the 1950s, the total death toll from asbestos exposure is in the millions.

Due to asbestos bans and strict regulations on how asbestos is handled in many high-income countries, death tolls in these countries are generally predicted to decline in the years to come.  However, the ongoing trade in white asbestos and millions of tonnes of asbestos remaining in the built environment mean there will likely be large numbers of deaths from asbestos for many decades to come.

Who gets asbestos diseases?
Those most likely to get an asbestos-related disease are those who are highly exposed to asbestos. Historically, this has included asbestos factory workers, miners, electricians, carpenters, plumbers, joiners, steelworkers, mechanics, firefighters, construction workers, dockers, shipwrights, and shipbreakers. Family members of these workers, and those living close to sites with significant levels of asbestos, have also been extensively impacted.

There has been an increasing awareness of asbestos diseases in professions not historically assumed to be at risk from asbestos exposure, such as teachers, nurses, or maintenance workers, through environmental exposure to asbestos in their workplace or their home.

Countries with high levels of recorded asbestos-related deaths per capita include the UK, Netherlands, Australia, Canada, and Belgium.

What asbestos products are the most dangerous?
One of the most dangerous asbestos products was Kent’s cigarettes, which briefly used blue asbestos as a filter in the 1950s.

The risk from asbestos comes when the fibres become air-borne. This is easily done for asbestos in some materials, like sprayed insulation. For asbestos materials that are fully encapsulated and sealed, the risk is lower, so long as the materials remain in that condition. However, when these materials are disturbed – even if indirectly, degrade, destroyed, or removed, the fibres can become air-borne and pose a health risk.