CHAPTER THREE – A BRIEF HISTORY OF MEDICAL AND INDUSTRIAL KNOWLEDGE OF ASBESTOS RISKS
Despite the widespread use of asbestos in the 19th Century, medical science was such that an understanding of a potential link between respiratory conditions and exposure to asbestos dust did not really begin to develop until the very end of that century.
The first warning was sounded in the Annual Report of the Chief Inspector for Factories and Workshops of 1898 in which the following passage was written:
“The evil effects of asbestos dust have also attracted my attention, a microscopic examination of this mineral dust which was made clearly revealed the sharp, glass-like jagged nature of the particles and where they are allowed to rise and to remain suspended in the air of a room, in any quantity, the effects have found to be injurious as might have been expected…”1
The first substantive piece of research in relation to asbestos and its risks to health is generally attributed to that of William Cooke who wrote a piece in the British Medical Journal in 1924. William Cooke was a pathologist who had performed several autopsy’s on patient’s who had died at a relatively young age, from pulmonary fibrosis (a lung disease which causes extensive scarring to the inner lining of the lungs). In performing those autopsies, he noted the presence of asbestos fibres within the inner lung tissue and the presence of scarring around them. He termed the cause of death therefore as ‘asbestosis’.
It should be stressed that other deaths had occurred where autopsies had revealed extensive presence of asbestos fibres within the inner lung tissues. However, it is generally William Cooke’s article in 1924 which really focused the spotlight on asbestos and risks to health.
On the back of the article, the Government commissioned its then Chief Inspector of Factories, Edward Merewether and a Senior Engineer, Charles Price, to report on the status of the health of workers within the asbestos industry. That report2 demonstrated that asbestosis was present in up to a third of those workers who were still working within the industry and that the presence was even higher (up to 80%) in those who had been working in the industry for over 20 years. The conclusion was that ‘the inhalation of asbestos dust over a period of years results in the development of a serious type of fibrosis of the lungs.’3 It went on to say; “It seems probable, therefore, although further research is very necessary, that not only is a certain minimal quantity of the dust required for the production of a generalised fibrosis, but that inhalation of the dust in high concentration results in the production of a more marked degree of fibrosis in a shorter time, than when the concentration is low.”4 It was followed up by a further report by the same authors in 19315. The guidance from the reports was to encourage the suppression of dust though further research into how that could be done was intimated to be required.
At that time though, it was thought that the issue was confined to the asbestos producing industry, and even then, only in those who had had a high level of exposure over a prolonged period of time.
In 1931 the Asbestos Industry Regulations consequently became enacted. They became effective in 1933 and sought to introduce control over exposure and to reduce it. Again, though focus was on high-level exposures which ought to be prevented by the suppression of dust and the installation of ventilation to dilute concentration levels. The Regulations also required a degree of medical surveillance over works and, importantly, also made asbestosis a condition for which compensation could be claimed. There remained relatively little knowledge about other asbestos-related conditions which could also affect those exposed to asbestos dust.
In 1932 the Home Office investigated the risks of asbestos further and published their report ‘Asbestosis-Inquiry into the Existence of the Disease in Packers of Manufactured Articles’. That report found: “As a result of this enquiry we have formed the opinion that certain workers whose occupation is nominally that of packer, storekeeper or warehouseman, are exposed to a definite though very variable risk of contracting asbestosis.”6. That report indicated that the risks were prevalent to those not directly exposed to the dust in the course of their employment but who were exposed to background levels of dust of far lower concentrations.
There then came the Factories Act 1937, which prohibited, at section 47, exposure to ‘any dust …of such a character and to such an extent as to be likely to be injurious or offensive … or of any substantial quantity of dust of any kind.’ The same, on its face, therefore include exposure to asbestos dust, though the phrase ‘substantial quantity’ was undefined. In 1939, the Annual Report of the Chief Inspector of Factories for 1938, discussed that section. The end comment read: “It is not many years ago when the dust of asbestos was regarded as innocuous, while today it is recognised as highly dangerous.”
Despite Regulation, however, the use of asbestos continued in the UK and indeed, its use increased throughout the 2nd World War.
In the late 1940s Merewether again looked into the risks posed by asbestos in his ‘Annual Report of the Chief Inspector of Factories for the year 1947’. He found that lung cancer had also been reported in 13.2% of cases of asbestosis that he had looked at. Further research was done by S.R. Gloyne in 1951 in which he found lung cancer present in 14.1% of autopsies performed on those with asbestosis. In 1949 the Deputy Chief Inspector of Factories was referred to the issue of asbestos lagging in power stations and the application of the 1931 Regulations. The conclusion was:
“The Regulations do not apply to the removal of old lagging, nor to the actual application of the insulation to steam pipes etc. In regard to dusty processes which are outside the application of the Regulations, all possible steps should be taken against the inhalation of dust and the standards of the Regulations should be followed as far as practicable. Section 47 of the Factories Act 1937 requires that all practicable measures be taken to protect persons against the inhalation of inter alia, injurious dust and that when practicable, exhaust ventilation is to be provided. Apart from exhaust ventilation, other safeguards such as using suitable appliances for the operations, wearing respirators, avoiding unnecessary scattering and spillages and damping material before cleaning up, are of importance.”
By this time, the link between smoking and lung cancer had previously been made by Richard Doll in the early 1950s. The increasing presence of lung cancer in cases where an asbestos-worker had also developed asbestosis, however, began to be more closely monitored. Accordingly, in 1955 Doll published further research which looked, for the first time, at the presence of lung cancer in workers exposed to asbestos7. Doll concluded that “The extent of the risk of lung cancer over the whole period among the men studied appears to have been of the order of 10 times that experienced by other men.”
At that point though, it was thought that the measures introduced in the 1931 Regulations had had a positive effective in reducing the numbers of asbestos-related injuries which had gone on to be suffered. It was believed to be too soon after their implementation to determine anything more in relation to future risks.
In 1960 further research was, however, published by another group of pathologists J.C. Wagner, C.A. Sleggs, and P Marchand based on research commissioned in South Africa8. The research focused on 33 cases of mesothelioma (a malignant tumour of the pleura which had become more commonly seen in the Cape Province) of which it was made known that 28 had links to the Cape asbestos industry (either by direct employment or by their vicinity to mines) and where four of the other cases had involved men exposed to asbestos in other industries. Asbestos fibres were only found in 8 cases of those examined, though circumstantial evidence of exposure to asbestos dust was found in relation to the other cases. The paper is therefore widely credited as being the first to establish the link between mesothelioma and asbestos exposure – even on a low-level exposure basis and where exposure had not occurred during employment.
Accordingly, by the early 1960s, there were three known asbestos-related injuries; asbestosis, lung cancer, and mesothelioma.
At the same time, in the UK, the Ministry of Labour published an industry publication entitled ‘Toxic Substances in Factory Atmospheres’ which contained the first reference to exposure parameters to asbestos dust. In the ‘normal working day’ they specified that the Threshold Limit Value for Asbestos dust was 177 particles per cubic centimetre of air (ppcc) which translated to 5-30 fibres/ml. This was subsequently updated in 1966 and 1968 in respect to other substance exposures, but the threshold remained the same in each revision for asbestos.
In 1962, Wagnar published further research9. In 1964, W.G. Owen published a further paper on the link between asbestos exposure and mesothelioma picking up on the research by Wagner et al, and this time focusing on UK cases10. In his research, 17 cases of diffuse mesothelioma were examined of which 14 cases had strong evidence of asbestos exposure, and exposure was suspected in the remaining. All told, the study covered both workers who had directly handled asbestos and others who had worked in clerical roles in offices which had a presence of asbestos dust. The study concluded that “exposure to asbestos is a major factor, and possibly an essential one in the causation of diffuse mesothelioma”11. Again, it was noted that the level of exposure to establish that causation, need not be high. Similar findings and conclusions were made by Elmes, McCaughy and Wade, through their research published in February 196512.
Also, in 1965, Newhouse and Thompson published more in-depth research into UK case of mesothelioma13. This time, 76 cases were examined, 23 of whom had direct asbestos exposure at work, 53 had no recorded exposure to asbestos, but 9 of those had second-hand exposure from people who worked at an asbestos factory and who they came into regular contact with, and another 11 worked within half a mile of an asbestos factory. This seminal paper concluded that mesothelioma could arise from even minimal second-hand and indirect exposure to asbestos dust and is regarded as something of a ‘watershed’ in industrial knowledge of low-dose exposure risks.
On 31st October 1965, soon after publication of Newhouse and Thompson’s research paper, The Sunday Times published a headline article which discussed the research and the risks to health which flowed from exposure to asbestos. The article caused more widespread knowledge of asbestos risks beyond the industrial and medical sectors. Soon after, Mesothelioma caused by occupational exposure to asbestos became a prescribed industrial disease in August 1966.
A short time later, in December 1966, the Asbestosis Research Council published ‘Recommended Code of Practice for Handling Asbestos Products Used in Thermal Insulation’. That set out extensive guidance to the handling of asbestos in that industry, including; dampening procedures, the need for segregation when asbestos is cut or stripped, the use of protective sheeting within which dust should be collected and the installation of permanent or portable ventilation. Again, medical supervision and surveillance of workers was outlined.
On 3rd January 1968 The UK Medical Advisory Panel published research into crocidolite and highlighted its carcinogenic properties14. They recommend the exclusion of crocidolite wherever possible and called for greater controls to be more rigidly applied commenting that rapid expansion in volume and variety of asbestos usage had created problems in terms of the number of persons becoming exposed and the unsatisfactory working conditions which were persisting in parts of the industry. It was particularly noted that the potency of crocidolite was such that a safety level cannot be established or regulated.
Following on from that work, the British Occupational Hygiene Society published guidance on exposure parameters for chrysotile15 and, for the first time, regulation began to differentiate between the different types of asbestos. Nonetheless, the report still referred to the risk posed by chrysotile dust as “small” and therefore set exposure limits which, in their view, “could be tolerated for a lifetime without incurring undue risks.” and accordingly sought to reduce the risk of developing asbestosis to 1% by setting exposure parameters to chrysotile over 10, 25 and 50 year exposure periods.
The culmination of the research emerged during the latter half of the 1960s caused a review of the 1931 Regulations by HM Factories Inspectorate and eventually culminated in further regulation in the form of the 1969 Asbestos Regulations. Notably, the 1969 Regulations had far wider application than their predecessor. They set maximum exposure levels and applied to all work sites and not, as previously, to asbestos producing factories or facilities as before. They applied to all processes involving the use of asbestos and all items which were made up wholly or partly of asbestos16. These Regulations will be considered in more detail in Chapter 4, but Regulation 5 imposed strict obligations and requirements on employers and occupiers of premises where asbestos is used and all contractors on sites where asbestos was used or removed.
Accompanying the new Regulations was Technical Data Note 1317 (‘TDN 13’) issued in early 1970 and which set exposure parameters as follows over a 4-hour weighted exposure period:
Chrysotile & Amosite: 2 fibres/ml
Crocidolite: 0.2 fibres/ml
These parameters were specifically for factory inspectors to determine whether exposure was “to such an extent as is liable to cause danger to the health of employed persons” under Regulation 2(3) of the 1969 Regulations.
From there, industry knowledge, led largely by government guidance, began to emit tighter and tighter restrictions with crocidolite ceasing to be imported from 1970 onwards.
In 1976 an Advisory Committee on Asbestos was set up by the Secretary of State for Employment. The aim of the Committee was to report on the risks posed by asbestos to workers and the general public, as well as risks from asbestos products and waste.
Also, in 1976, the Health and Safety Executive published Guidance Note EH1018. That maintained the exposure parameters which had been endorsed by Technical Note 13 but, crucially, and for the first time, gave the wide-ranging guidance that “Exposure to all forms of asbestos dust should be reduced to the minimum that is reasonably practicable.”
In 1979 the Advisory Committee produced their final report. Their ultimate conclusion was that the control of useful but hazardous materials is preferable to prohibition of the substance. Prohibition was confirmed though in relation to the importation and manufacture of crocidolite products and to the application of asbestos material through spraying. The Committee encouraged the substitution of asbestos products wherever possible, and recommendations made to reduced exposure thresholds further to those specified in EH10 and TN13 previously and called for regulatory backing to reduce exposure to the ‘lowest level reasonably practicable’. Increased medical supervision was also recommended to try and detect symptoms in workers as early as possible and to ensure that data could properly be obtained and recorded. PPE and effective ventilation in the workplace were also recommended.
In 1983, the HSE revised the 1976 EH10 Note in accordance with the recommendations in the Advisory Committee’s final report. As such, they reduced the threshold exposure values taken over a weighted 4-hour exposure period:
Chrysotile: 1 fibres/ml
Amosite: 0.5 fibres/ml
Crocidolite: 0.2 fibres/ml
In addition, further guidance was given to employers about how to reduce exposure to the ‘lowest level reasonably practicable’.
In 1985, The Asbestos Prohibition Regulations 1985 came into effect which prohibited the importation and use of amosite and crocidolite. Likewise, it was also prohibited to supply products containing those materials under The Asbestos Products Safety Regulations 1985. Products containing chrysotile and amphibole asbestos remained widely available on the market however, but were required to be appropriately labelled. Following on then, in 1987, The Asbestos Products Safety (Amended) Regulations 1987 came into force, and then later, in the same year, The Control of Asbestos at Work Regulations 1987. These latest Regulations were more ambitious and more substantive than their predecessors and required the total prevention of exposure to asbestos at work or to reduce the level of exposure to the lowest level reasonably practicable. These Regulations will be discussed in more detail in the preceding chapters.
More Regulation occurred over the coming years until, finally, in 1999 with the passing of The Asbestos (Prohibitions) (Amendment) Regulations, when chrysotile was also banned in the UK. Those regulations came into effect on 24th November 1999.
Following the prohibition on asbestos products being used in new products and installations, there has been further regulation, most notably The Control of Asbestos at Work Regulations 2002 and The Control of Asbestos Regulations 2006 – these will be discussed in more detail in subsequent chapters.
A highlighted version, for easier, and more fleeting reference, can be seen in the timeline at the conclusion of the Chapter.
It is hoped that that historical narrative provides a framework for some of the important medical, industrial, and indeed the regulatory developments which occurred from the late 1870s when the use of asbestos began to be commercialised.
1870s – Commercial Asbestos Sales Commence
1900 – First cases of Asbestosis noted
1924 – William Cooke article on asbestosis
1930 – Merewether & Price HM Factories Report
1931 – Asbestos Industry Regulations 1931
1937 – s47 of Factories Act 1937 comes into effect
1955 – Doll Research on asbestos exposure and lung cancer
1960 – Wagner et al on asbestos exposure and mesothelioma & Ministry of Labour’s ‘Toxic Substances in Factory Atmospheres’ laying down the first exposure parameters for asbestos
1965 – Newhouse & Thompson paper on asbestos exposure and mesothelioma in the UK
1968 – UK Medical Advisory Panel report recommends ban on crocidolite
1968 – British Occupational Hygiene Society recommends exposure parameters for chrysotile
1969 – Asbestos Regulations 1969
1970 – Ministry of Labour Publishes TN13 setting exposure parameters for crocidolite, chrysotile and amosite
1976 – HSE published Guidance Note EH10 reducing exposure parameters to crocidolite, chrysotile and amosite or to ‘lowest level reasonably practicable’
1983 – EH10 revised and further reductions made to exposure parameters to crocidolite, chrysotile and amosite
1985 – The Asbestos Prohibition Regulations 1985 – bans crocidolite
1987 – The Control of Asbestos at Work Regulations 1987
1999 – The Asbestos (Prohibitions) (Amendment) Regulations 1999 – bans the use of asbestos in the UK
2‘Report on the effects of asbestos on the lungs and dust suppression in the Asbestos Industry’ by Merewether & Price published in 1930.
5‘Report on Conferences between Employers a& Inspectors concerning Methods for Suppressing Dust in Asbestos Textile Factories’ by Merewether & Price published in 1931
7‘Mortality from Lung Cancer in Asbestos Workers’ published 1955 in the British Journal of Industrial Medicine: 485 – 490
8‘Diffuse Pleural Mesothelioma and Asbestos Exposure in the North Western Cape Province’ published in 1960 in the British Journal of Industrial Medicine: 260 – 271
9‘The Pathology of Asbestosis in South Africa’ 1962
10‘Diffuse Mesothelioma and Exposure to Asbestos in the Merseyside Area’ British Medical Journal 1964, 214 – 218
12Diffuse Mesothelioma of the Pleura and Asbestos’ British Medical Journal: 350 – 353
13Mesothelioma of Pleura and Peritoneum Following Exposure to Asbestos in the London Area’ British Journal of Industrial Medicine October 1965: 261 – 269
14‘Problems arising from the use of asbestos: memorandum of the Senior Medical Inspector’s Advisory Panel’ 1967
15‘British Occupational Hygiene Society Hygiene Standards for Chrysotile Asbestos Dust’ 1968
17‘Standards for Asbestos Dust Concentration for Use with the Asbestos Regulations 1969’ by Department of Employment and Productivity published 1970
18Published December 1976