Asbestos and Public Health
• Asbestos consists of pliable mineral fibers with attractive properties such as resistance to heat, electrical conductivity, sound insulation etc. First used in UK in1857.
• Was considered a “miracle mineral” and commonly used within building as a fire and heat resistant material.
• It became clear later (from end of 19th C) that inhalation of asbestos fibres causes diseases such as illnesses,
including mesothelioma and asbestosis.
• Wonder material !
occupational and public health hazard!
• Regulations on exposure to asbestos and EQOs have changed considerably over time to reflect increasing knowledge about health effects and changing tolerance of damage to public health.
A lung macrophage trying to engulf an asbestos
• Asbestos are long thin fibers that cannot be dealt with by the lung macrophages system.
• Any similarity with a carbon walled nanotube?
• Research ongoing.
Asbestos time line
• In 1920s large section of factory workers from the asbestos industry was studied revealing that ! suffered from pulmonary fibrosis.
• Regulations developed including industrial hygiene standards, medical examinations, and inclusion of the asbestos industry into the British Workers’ Compensation Act.
• In the US litigation started in 1930s (will come to UK case later).
• Conflict between workers health and company profits begins.
• 1931 – Asbestos Industry Regulations established.
– set a “safe” level that allowed 1 worker in 3 to get asbestosis
after 15-19 years exposure. SAFE?
• Up to 1960 – 63 papers on hazards of asbestos published. 52 independent papers showed asbestos to be a dangerous source of asbestosis and lung cancer; largely ignored. 11 sponsored by industry presented virtually the opposite conclusions.
• 1968 – British Occupational Hygiene Society offers a safety standard for asbestos of 2 fibres/ml – incorporated into the 1969 Asbestos Regulations.
• 1 worker in 10 could contract asbestos related disease at this level.
• 1970 The 1969 Asbestos Regulations introduced.
• 1983 The Asbestos (Licensing) Regulations are enacted under the Health and Safety at Work Act
1974.They cover the most hazardous jobs such as asbestos stripping or removal.
• 1985 Asbestos (Prohibition) Regulations introduced and later amended in 1992. Prohibit import, supply and
use of blue/brown asbestos, products containing them, the spraying of asbestos and installation of asbestos
• 1987 The Control of Asbestos at Work Regulations were introduced and later amended in 1992.
• 1995 The HSE sharply revised upwards estimates of asbestos-related deaths between 1995-2025 and started an awareness campaign amongst maintenance workers.
Asbestos and public health
Occupational Control Limits
For blue and brown asbestos
• i) 0.2 fibres/ml of air averaged over any continuous period of 4 hours
• ii) 0.6 fibres/ml of air averaged over any 10 minutes
For white asbestos
• i) 0.5 fibres/ml of air averaged over any continuous period of 4 hours
• ii) 1.5 fibres/ml of air averaged over any continuous period of 10
For members of public limit is 0.01 respirable fibres/ml of air.
Level of acceptability of risk has changed over time and this is common for many pollutants.
Around 2,000 people a year in Britain die from mesothelioma – but hard to prove how many related to asbestos exposure. Can be decades in between exposure and cancer development.
What does the case of asbestos tell us?
• The latent gap between exposure and disease can make causality difficult to prove.
• What are considered to be safe standards can change over time. WHY?
• There is a trade off between industrial competitiveness and health and safety.
• Public exposure and occupational exposure
standards are very different.
• It is important to understand the health impact of
new materials before common industrial use!
• Quote from Larry Summers the Chief Economist at the World Bank in 1991.
“The measurements of the costs of health impairing pollution depends on the foregone (lost) earnings from increased morbidity and mortality. From this point of view a given amount of health impairing pollution should be done in the country with the lowest cost, which will be the country with the lowest wages. The economic logic behind dumping toxic waste in the lowest wage country is impeccable and we should face up to that.”
• Should the level of allowed pollution really depend on wage earning power of affected population? Does this imply an uneven value to human life and health?