Occupational exposure to asbestos is a higher risk for those who work in:
- civil engineering
- boat building
- ship breaking
- industrial sectors.
Workers in these sectors usually encounter asbestos during maintenance, refurbishment or demolition activity.
In countries where asbestos is still used, other workers will be exposed, especially those involved in the manufacture, use or installation of products using asbestos-containing materials (ACMs).
Plus, workers involved with infrastructure construction, emergency services or clean-up operations after a natural disaster will be at risk of occupational exposure to asbestos. This is because asbestos may be present in post-disaster environments.
Harmful effects from asbestos have been reported in medical papers since 1924. But it wasn’t until 1955 that breathing in asbestos fibres was shown to cause lung cancer and, in the 1960s, mesothelioma.
Blue and brown asbestos are the most harmful, but white asbestos can also cause asbestos-related diseases.
This lung condition can occur when asbestos fibres breathed into the deepest parts of the lungs cannot be removed by the body’s defences. They damage cells that are usually repaired by the body, creating scar tissue. This process is called fibrosis. It shows up as mottled spots or smears on x-rays. Scarring destroys lung tissue and reduces the lung’s ability to take in oxygen. It can cause pain and breathlessness. Asbestosis usually occurs by breathing in fibres over many years. However, it can also be due to high-concentration exposures of a short duration. Generally, the greater the concentration of asbestos dust and the number of years a person is exposed, the higher the chance of developing asbestosis.
This is a malignant lung tumour characterised by uncontrolled cell growth in lung tissues. Most primary lung cancers are carcinomas, which produce common symptoms of coughing (including coughing up blood), weight loss, shortness of breath and chest pains.
Asbestos fibres can also affect the lining of the lungs, causing the development of a malignant and incurable cancer called mesothelioma. This tumour causes fluid build-up in the pleura and pain in the chest. Deaths from mesothelioma typically occur 20 to 40 years following exposure.
Asbestos can also cause scaring to the pleura or a build-up of fluid in this space in the lungs. While pleural plagues are benign, they can sometimes cause pain and difficulty in breathing and may need to be removed surgically.
Research, carried out between 1971 and 2005 in the United Kingdom, found that asbestos causes lung disease and that if the worker is also a smoker, this significantly increases the risk. Any co-exposure to tobacco smoke and asbestos fibres increases the risk for lung cancer (Frost G, Darnton A, Harding AH. The effect of smoking on the risk of lung cancer mortality for asbestos workers in Great Britain (1971–2005). Annals of Work Exposures and Health 2011; 55(3):239-247).
The International Agency for Research on Cancer (IARC) has reaffirmed that all types of asbestos can cause cancer. In addition to lung cancer and mesothelioma, it identified two other types of cancer that are caused by asbestos: larynx and ovarian. Medical evidence shows that other cancers linked to asbestos can include peritoneal, colorectal, stomach and pharyngeal.