Asbestos Dust: How Dangerous Is Exposure and What Are Its Health Effects?

Asbestos was once widely used in construction and industrial applications because of its strength, durability and resistance to heat. Its widespread use, however, has left behind a continuing occupational health challenge.

When asbestos-containing materials are disturbed, they can release microscopic fibres into the air. Exposure to these fibres can cause serious diseases, including lung cancer, mesothelioma and chronic respiratory conditions. The consequences may not become apparent until many years or even decades after exposure.

According to the World Health Organization (WHO), all forms of asbestos, including chrysotile, are carcinogenic to humans. WHO and International Labour Organization estimates for 2016 attribute more than 200,000 deaths globally to occupational asbestos exposure, representing more than 70% of deaths from work-related cancers. 

Asbestos is a group of naturally occurring mineral fibres. The six main forms are chrysotile, amosite, crocidolite, actinolite, anthophyllite and tremolite.

The material was historically used in numerous commercial applications because of its physical properties. Building materials are among the most significant sources of concern because asbestos can remain in place for decades.

Asbestos dust is generated when asbestos-containing materials are damaged, deteriorate or are disturbed. Activities such as construction, maintenance and demolition can therefore release asbestos fibres into the air and create opportunities for exposure.

The risk does not necessarily disappear simply because asbestos is no longer being actively used. Older buildings can still contain asbestos-containing materials, meaning workers may encounter the material long after it was installed.

How Harmful Is Asbestos Dust?

The effects of asbestos dust can be severe. How harmful is asbestos dust can depend on the level and duration of exposure, but WHO has assessed all forms of asbestos as carcinogenic to humans.

Exposure to asbestos can cause lung cancer, mesothelioma and cancers of the larynx and ovary. It can also cause asbestosis, a chronic respiratory disease involving fibrosis of the lungs.

The scale of the problem is reflected in global estimates. Occupational asbestos exposure was associated with nearly 4 million disability-adjusted life years in 2016, in addition to more than 200,000 estimated deaths.

Another concern is the long latency period of asbestos-related diseases. Someone exposed to asbestos may not develop symptoms immediately and may only be diagnosed many years after the exposure occurred.

The dangers of asbestos dust arise when microscopic fibres become airborne and are inhaled. The risk is particularly relevant in workplaces where asbestos-containing materials are being disturbed.

Construction workers are among the groups facing potential exposure. A systematic review contributing to the WHO/ILO Joint Estimates found evidence indicating that a substantial proportion of manual workers in the global construction industry are exposed to asbestos. However, the review classified the available evidence as low quality and called for further research.

Exposure can also occur during asbestos mining and processing and during the production and use of asbestos-containing products. Workers trimming or fitting such products may also come into contact with asbestos fibres. 

There is no single amount of exposure that can be used to determine whether an individual will develop an asbestos-related disease. The circumstances of exposure, including the extent and duration of exposure, are important considerations.

Repeated occupational exposure can be a particular concern because workers may encounter asbestos fibres while performing routine tasks involving older materials.

The absence of immediate symptoms should not be interpreted as evidence that exposure was harmless. Asbestos-related diseases can take decades to develop, which means the health consequences of exposure may emerge long after the original incident.

Construction, maintenance and demolition workers can potentially encounter asbestos where the material has previously been used.

Other potential sources of occupational exposure include:

• Mining and processing asbestos

• Manufacturing asbestos-containing products

• Fitting and trimming asbestos-containing products

• Building maintenance

• Demolition

• Asbestos removal

• Handling asbestos-containing building materials

Historically, asbestos has been used in products including asbestos-cement roof tiles, vehicle brake shoes, brake pads and clutches.

Asbestos-containing materials can also become a concern when they deteriorate or are disturbed during building maintenance, demolition and construction-waste disposal. Damage to buildings following natural disasters can create additional exposure risks where asbestos materials are present.

The effects of asbestos dust can involve both cancer and chronic respiratory disease.

Asbestosis causes fibrosis of the lungs and can result in significant long-term respiratory impairment. Asbestos exposure is also associated with lung cancer, mesothelioma and cancers of the larynx and ovary.

The risk of lung cancer is particularly concerning when asbestos exposure occurs alongside tobacco smoke. WHO reports that co-exposure to tobacco smoke and asbestos fibres substantially increases lung cancer risk, with heavier smoking associated with a greater risk. 

Dr. Munish Kumar Raizada, while discussing the health consequences of asbestos exposure, explains that inhalation of asbestos fibres can cause pulmonary fibrosis, resulting in scarring and stiffening of the lungs. As the condition progresses, it can impair normal lung function and make breathing increasingly difficult.

“Exposure can lead to fibrosis and stiffening of the lungs. Patients may develop symptoms such as dyspnea, or shortness of breath, and tachypnea, which refers to abnormally rapid breathing. In more advanced cases, cyanosis, a bluish discoloration caused by inadequate oxygenation, may also occur,” Dr. Raizada said.

The symptoms associated with asbestos-related lung disease can develop gradually and may appear many years after the initial exposure. OSHA’s medical surveillance guidance for asbestos also identifies shortness of breath as a symptom associated with asbestosis, which is a form of pulmonary fibrosis caused by asbestos fibres accumulating in the lungs. 

OSHA Safeguards for Workers

In the United States, asbestos exposure in the workplace is regulated by the Occupational Safety and Health Administration (OSHA). OSHA has specific standards covering asbestos exposure in construction, general industry and shipyard employment.

These standards include measures such as exposure monitoring, regulated work areas, engineering and work-practice controls, respiratory protection and medical surveillance for workers covered by the applicable requirements. OSHA also requires employers to control airborne asbestos exposure and, where necessary, supplement engineering controls with respiratory protection. 

The measures are intended to reduce workers’ exposure to airborne asbestos fibres, but workplace controls do not eliminate the need for proper asbestos handling, removal and other safety procedures.

Preventing asbestos-related disease begins with preventing exposure. WHO identifies stopping the use of all forms of asbestos as the most effective way to eliminate asbestos-related diseases. More than 50 WHO Member States have already introduced legislation prohibiting asbestos use. 

However, asbestos-containing materials remain present because of decades of historical use. This makes exposure control important during maintenance, demolition and asbestos removal.

In industrial and manufacturing environments, engineering controls can form part of a broader workplace strategy for controlling airborne dust and protecting workers from hazardous particles. Industrial dust-collection systems, including baghouse, cartridge and portable dust collectors, can be used for appropriate dust-control applications where airborne particulate matter is generated.

The specific control measures required depend on the material and work process. Dust collection and filtration should not be considered a substitute for proper asbestos-management, removal and occupational-safety procedures. Where asbestos is involved, preventing disturbance and following established procedures for handling and removal remain essential.

The legacy of asbestos use means the risks can continue long after its commercial use has been restricted.

Older buildings may contain asbestos-containing materials that workers encounter during maintenance, renovation or demolition. Asbestos-related diseases also have long latency periods, meaning deaths and ill health can continue to occur for many years after exposure.

For this reason, WHO emphasizes the importance of continued awareness, disease surveillance and training for medical staff, labour inspectors and occupational health professionals.

Asbestos dust can be a serious occupational health hazard when asbestos fibres become airborne and are inhaled. All forms of asbestos are carcinogenic to humans and have been linked to cancers including lung cancer and mesothelioma, as well as chronic respiratory disease.

With more than 200,000 occupational deaths estimated globally from asbestos exposure, preventing exposure remains the central priority. Eliminating asbestos use and replacing it with safer materials is the most effective approach, while appropriate workplace controls and safe procedures are essential when asbestos-containing materials are already present.

For industries dealing with airborne dust, effective dust collection and filtration can be an important component of broader exposure-control measures. However, asbestos requires specific handling and removal procedures, and no single filtration system should be treated as a replacement for those safeguards.

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