HSE has today confirmed that white asbestos (chrysotile) is a major health hazard.All
HSE estimates that up to 4,000 lives could be lost over future years unless steps are taken now to
manage the risks from the asbestos present in commercial buildings. Not only would any exemption given to white asbestos would be unjustifiable scientifically, it would also make the challenging task of assessing and managing the risks from asbestos almost impossible.
Many building products contain a mixture of the three different types of asbestos. For this reason the existing regulations for asbestos in the workplace require that where the type of fibre cannot be identified, it must be assumed that the more hazardous forms of asbestos are present.
Further advice on asbestos in buildings is contained in the free HSE leaflet ‘Managing Asbestos in Premises’.
Building maintenance workers might be exposed to an estimated average of 0.1 fibres per millilitre
of white asbestos over a working life which would create a risk equivalent to one death in 5,000 workers.
But there is considerable uncertainty in this estimate which could be lower or, under a more cautious
reading of the evidence, could be significantly higher, perhaps as high as one in 750.
HSE’s John Thompson, said:
” The scientific evidence does not provide us with an easy answer to the question of just how dangerous
chrysotile – white asbestos – really is. Our belief, based on the best available scientific evidence,
is that the risk is real, and we must act accordingly.”
The technical arguments supporting HSE opinion on white asbestos are set out in a position paper attached to this notice.
Notes to editors
1. Recent press articles have suggested that chrysotile (white asbestos) is harmless and should be
exempted from new rules due to come into force later this year that require those responsible for
commercial buildings to manage any asbestos in the premises.
2. The Health and Safety Commission will soon be putting forward new legislation to introduce a
new duty which will seek to deal with the risks of asbestos in buildings. A Consultative Document
setting out the latest proposals was published on 21 November 2001. Responses should be sent to
Ian Gooday at the HSE, 6th Floor, South Wing, Rose Court, 2 Southwark Bridge, London SE1 9HS by 19 February 2002.
3. The need for this action led directly from research carried out by Professor Julian Peto and HSE
epidemiologists in 1995 which showed clearly that of the 2,000 – 3,000 people each year that die from
asbestos related diseases, over 25 per cent worked in the building and maintenance trades. Many were
completely unaware that they had worked with asbestos containing materials. Despite current controls
and the fact that asbestos can no longer be installed, HSE believes that significant risks remain in the
800,000 commercial buildings thought to still contain asbestos. This remaining risk could lead to
4,000 future deaths in the coming years, peaking at 80 deaths a year. All of these are preventable.
4. Under the duty to manage, those responsible for workplace premises will be required to find out
whether asbestos is present in their buildings (or presume that it is), assess the risk of exposure to
asbestos fibres, and prepare and implement plans to ensure that no one is inadvertently exposed to
asbestos in the future. The duty will apply to all types of asbestos found in building materials – including blue
brown and white forms of the mineral, as HSE considers all of these to be potentially cancer-causing.
The type of asbestos will be a factor in the risk assessment made to decide how to manage the material.
The number of deaths caused by mesothelioma and asbestosis are increasing, and around 1800 (nearly 1600 mesotheliomas) were recorded in 1999. These are both associated almost entirely with past exposure to asbestos fibres (of all types). This exposure will also have led to deaths from lung cancer, but since these cannot be individually identified case-by-case their number cannot be determined with any degree of certainty. Observations carried out on groups with known exposure to asbestos suggest that there is a predictable relationship between the number of mesothelioma deaths and the number of lung cancer deaths that can be ascribed to asbestos. This relationship is different for different fibre types, and probably for different intensities of exposure. The extrapolation from mesothelioma deaths to lung cancer deaths cannot therefore be a precise one, although HSE’s best estimate is that it is reasonable to assume one or two lung cancer deaths for each current mesothelioma death.
As the epidemiological evidence accumulated through the 1950s and 1960s it began to suggest that the different asbestos fibre types presented different degrees of cancer risk, particularly for mesothelioma. By the time the 1969 Asbestos Regulations were drafted it was sufficiently clear for different control limits to be proposed, with the most stringent for crocidolite. The later Control of Asbestos at Work Regulations 1987 also set different limits.
Whilst the evidence linking high exposures of chrysotile with cancer is compelling [Rochdale pre-1933 cohort, Quebec miners, animal studies ], there is more uncertainty about the degree of risk at much lower levels. However, chysotile remains a category 1 carcinogen, [IARC 1977, 1979 and 1982, IPCS, EC].
Although the qualitative difference between the different fibres is very widely accepted in the scientific community, there is no real consensus on the quantification of those differences. A recent study [Mc Donald et al (2001)] suggested that, on the basis of the quantities of different fibres found in mesothelioma case lungs, approximately 10% of all mesothelioma deaths could be attributable to exposure from white asbestos. However such an estimate is difficult to make with any degree of scientific precision.
The first comprehensive review which attempted to quantify these relative risks was carried out by Hodgson and Darnton. Their paper stated that whilst the risks from chrysotile were significantly less than those from amosite or crocidolite, they were not negligible. Furthermore, they acknowledged the considerable degree of uncertainty in the quantification of these risks. This uncertainty would make any uncoupling of chysotile from asbestos legislation highly unwise.
What makes asbestos unique amongst recognised carcinogens is the amount of all forms of the mineral permanently present in the workplace, and the relative ease by which fibres can be released, for example by maintenance work on buildings. This is particularly true in the built environment, where hundreds of thousands of tonnes of asbestos were used (mainly between 1950 and 1970) in building materials, and where many every day tasks, such as maintenance work, can lead to the liberation of asbestos fibres. This makes it imperative that a precautionary approach is taken towards the control of exposure to all types of asbestos.
HSE guidance (such as MDHS 100) allows any assessment of the risk from asbestos in buildings to take account of the type of fibre found in the material (along with other factors such as the friability the material and the likelihood of it being damaged or disturbed). However, many building products contain a mixture of other forms of the mineral, giving them a greater overall risk than chrysotile on its own. For this reason, it is common practice for those engaged in asbestos work such as removal contractors to assume that the asbestos found in the product is amphibole – brown or blue – asbestos and take precautions accordingly.