Is all Asbestos the same?
Introduction
When I started learning about asbestos, I was told that there were three main types, and that these were known by their ‘colour’. In addition, I was informed that Chrysotile (white) asbestos was the ‘safer’ one, due to its wavy fibre form. Whereas Amosite (brown) and Crocidolite (blue) were the ‘unsafe’ ones, with Crocidolite being the really nasty one.
This understanding was reinforced in the British Health and Safety Executive asbestos risk assessment algorithm that provides risk ratings for the different types of asbestos as follows;
|
Type |
Risk rating |
|
Chrysotile only |
1 |
|
Brown (Amphibole asbestos excluding crocidolite) and mixtures (not blue) |
2 |
|
Blue (Crocidolite) and mixtures or type unknown (Health and Safety Executive, n.d., p. 1) |
3 |
This understanding was challenged firstly with the passing in New Zealand of The Health and Safety at Work Act 2015 and the related Health and Safety at Work (Asbestos) Regulations (2016) (Asbestos Regulations) (Ministry of Business, Innovation, and Employment, 2016). The Health and Safety at Work Act has a strong risk-based approach, and I noted that the Asbestos Regulations did not attribute a different level of risk to the different types of asbestos.
Then, the WorkSafe Good Practice Guidelines: Conducting Asbestos Surveys was published in October 2016. This document while heavily influenced by HSE 264 (Asbestos: The survey Guide), did not in the risk algorithm include any reference to asbestos type. (WorkSafe New Zealand, 2016, p. Appendix B) (Health and Safety Executive, 2012, p. 67).
I then started to think, what does this mean to me as an Asbestos Surveyor working in New Zealand. Do I need to reference the type of asbestos (as the British HSE requires) when assessing risk, or does it remain silent as per the WorkSafe Good Practice Guidelines? This blog will attempt to answer that question.
The Science
Why do some people consider Chrysotile to be ‘safer’?
“Studies have linked more than a dozen different diseases to asbestos exposure. Many of these diseases, such as mesothelioma and lung cancer, have a confirmed relationship with asbestos. Others, such as COPD and kidney cancer, are not directly caused by asbestos, but researchers suspect that exposure can increase a person’s risk for developing them.” (The Mesothelioma Center, n.d.)
Other research has indicated that the while all forms of asbestos are carcinogenic to humans, causing cancers of the lung, larynx, ovary and mesothelioma. The risk of contracting mesothelioma differs between the various types of asbestos fibres, with Chrysotile appearing to have a lower risk. (Schüz, 2013, pp. 441-442).
This type of research indicating a difference in risk levels has been seized on by those who want to promote the continued use of Chrysotile, and they have promoted it as the ‘safe’ asbestos.
The Chrysotile Institute, which has an objective to “Promote …. the safe use of chrysotile” states “The banning of chrysotile is inconsistent with all current scientific evidence.” (Chrysotile Institute, n.d.)
What is the research really showing?
When looking at scientific research it is always important to see who is paying for it, that is why the disclaimer statements at the end of research papers are vital. As Chrysotile accounts for 95% of all produced asbestos (Baur, 2015, p. 176), there is a strong incentive for this industry to fund research that promotes the use of Chrysotile.
The Hazards Magazine undertook some research on this topic and state:
“Britain has history on asbestos. It has the highest death rates from asbestos cancers in the world. It is also home to some of the industry’s most relied-upon scientists.
British scientists have shown a remarkable willingness to defend chrysotile – the most common and last remaining form of asbestos in commercial use - although some have proved less keen to declare their links to the industry, a Hazards investigation has established. It reveals the impact of this research is being felt at home and abroad.
When concerns were raised that workers at the Balangero chrysotile asbestos mine in northern Italy and nearby residents had developed cancers as a result of exposure to its dust, British scientists stepped in to question the link.
Two of the four authors of a 2015 Epidemiology, Biostatistics and Public Health (EBPH) paper – Fred Pooley and John Hoskins – are UK-based scientists. Their contribution, Critical reappraisal of Balangero chrysotile and mesothelioma risk, first disputed whether most of the cancers were asbestos cancer at all. In a belt-and-braces defence, it then claimed the “alleged” cancers were anyway caused by exposure to other forms of asbestos, adding there was “good evidence” to support this claim.
The paper directly implicated three other types of asbestos, noting: “All the evidence suggests that crocidolite, amosite and tremolite are responsible for the alleged mesothelioma cases at Balangero.”
But evidence soon emerged casting doubt on their claims and leading some to question their motives.” (O’Neill, 2016)
This position is reinforced in the paper by Baur, X., et al, where the authors state:
“The asbestos industry promotes the notion that chrysotile asbestos is safer than other forms of asbestos. This is reflected in a recently published paper by Bernstein on health risks of chrysotile asbestos. However, this paper is scientifically flawed, including only selected literature and limited clinical and scientific knowledge. Based mainly on his own published animal studies, frequently with a limited follow-up of 90-360 days, the author concludes that when properly controlled, cement workers can safely use chrysotile asbestos.
However, available literature provides abundant evidence to the contrary. Many studies demonstrate adverse health effects from chrysotile asbestos in human beings and animals. Based on this evidence, the International Agency for Research on Cancer (IARC) has classified chrysotile as a group 1 carcinogen.” (Baur, 2015, pp. 176-177)
There has been significant epidemiological research undertaken in recent times demonstrating the chrysotile cancer link as described by Baur, X. et al., including a study by Yano, E. et al. In this study they undertook a 25-year longitudinal study of 515 male asbestos plant workers exposed to only chrysotile at the Chongqin chrysotile asbestos plant in China. They concluded:
“The present study demonstrates that exposure to uncontaminated chrysotile asbestos only may be related to an increased risk of lung cancer to an extent comparable to that caused by mixed-type asbestos. In addition, it suggests that exposure to pure chrysotile can also cause mesothelioma.” (Yano, 2001, p. 542)
Similarly, Lenters, V. et all. in their paper on the importance of quality data when undertaking epidemiological research state “we concluded that for lung cancer potency, differences between chrysotile versus amphibole-exposed cohorts become difficult to ascertain when the analysis is restricted to studies with fewer exposure limitations. (Lenters, 2012, p. 886)
Baur, X., et al conclude by stating:
“The asbestos industry has promoted and funded research contradicting established knowledge. Bernstein’s most recent publication is based on selected literature and ignores both clinical and scientific knowledge. It undermines the World Health Organization (WHO) campaign to stop the use of all asbestos types, including chrysotile asbestos (all kinds of asbestos are carcinogenic). Independent, sound scientific findings provide evidence that chrysotile, like other forms of asbestos is causative in asbestos-related morbidity and premature mortality” (Baur, 2015, p. 178)
From this independent international scientific research, it can be seen that regardless of the type of asbestos, the morbidity and premature mortality risks are similar. Therefore, in a risk profile analysis there should not be any differentiation of risk profile based on the fibre type.
New Zealand’s Regulations
New Zealand’s Asbestos Regulations in Regulation 3 (1) define asbestos as:
“Asbestos means the asbestiform varieties of mineral silicates belonging to the serpentine or amphibole groups of rock-forming minerals, including the following:
(a) actinolite asbestos
(b) grunerite (or amosite) asbestos (brown)
(c) anthophyllite asbestos
(d) chrysotile asbestos (white)
(e) crocidolite asbestos (blue)
(f) tremolite asbestos
a mixture that contains 1 or more of the minerals referred to in paragraphs (a) to (f)” (Ministry of Business, Innovation, and Employment, 2016)
I now realise that the approach taken by the New Zealand Government in assigning equal risk follows the best international scientific research available, and therefore when the WorkSafe Good Practice Guidelines: Conducting Asbestos Surveys were published it was correct not to include any reference to the fibre type in the risk algorithm. To have included a reference to it would have been wrong on two counts, these being:
(a) It is not in accordance with reputable international scientific research.
(b) It is contrary to New Zealand law.
What should a PCBU do?
PCBU’s (as defined in Clause 17 of the Health and Safety at Work Act 2015 (New Zealand Government, 2015)), under the Asbestos Regulations need to undertake Asbestos Surveys for both Management and Demolition/Refurbishment purposes, and in doing so every PCBU needs to ensure that the surveys they receive and on which they base their decisions comply with New Zealand law.
In the absence of a New Zealand specific asbestos surveying course, WorkSafe has endorsed the British BOHS Proficiency Module P402 Surveying and Sampling Strategies for Asbestos in Buildings and BOHS W504 Asbestos and other fibres, as relevant starting qualifications in asbestos surveying. (WorkSafe New Zealand, 2016, p. 15) The danger with this approach though is that the trainees, will be trained to use the British Risk Algorithm which includes assessing fibre type in the risk profile.
In New Zealand a PCBU’s overriding duty is to eliminate or minimise exposure to hazards, see Regulation 5 and 28 of the Health and Safety at Work (General Risk and Workplace Management) Regulations 2016 below:
“5 Duty to identify hazards
A PCBU, in managing risks to health and safety, must identify hazards that could give rise to reasonably foreseeable risks to health and safety.
28 Managing risks associated with substances hazardous to health
(1) A PCBU must manage, in accordance with regulations 5 to 8, risks to health and safety associated with substances hazardous to health at the workplace.
(2) A PCBU who contravenes this regulation commits an offence and is liable on conviction, -
(a) for an individual, to a fine not exceeding $10,000:
(b) for any other person, to a fine not exceeding $50,000.” (Ministry of Business, Innovation and Employment, 2016)
Irrespective of whether or not people agree on the relative cancer-causing potential of Chrysotile, it is a known carcinogen, and therefore the best practice controls should also apply, which are to treat it in the same manner as all other types of asbestos.
A PCBU when commissioning a survey needs to check if the surveyor plans to use fibre type when assessing risk. If the Surveyor does intend to include the use of fibre type in the Risk algorithm, then it is my recommendation that the PCBU either:
(1) Requests that the surveyor uses the algorithm in the WorkSafe Good Practice Guidelines, and therefore complying with both New Zealand law and international best practice.
(2) If the surveyor insists on using fibre type in the Risk Algorithm, then the PCBU should chose a different surveyor, as the PCBU’s subsequent decisions may be made on misleading advice.
References
Baur, X., Soskolne, C.L., Lemen, R. A., Schneider, J., Woitowitz, H., Budnik, L. T., (2015, March 27). How conflicted authors undermine the World Health Organization (WHO) campaign to stop all use of asbestos: spotlight on studies showing that chrysotile is carcinogenic and facilitates other non-cancer asbestos-related diseases. International Journal of Occupational and Environmental Health, 21, 2015(2), 176-179. doi:10.1179/2049396714Y.0000000105
Chrysotile Institute. (n.d.). Frequently asked questions. Retrieved 16 March, 2018, from Chrysotile Institute: http://www.chrysotile.com/en/faq.aspx
Health and Safety Executive. (2012). Asbestos: The Survey guide. Retrieved 12 March 2018, from Health and Safety Executive - Guideance: http://www.hse.gov.uk/pubns/priced/hsg264.pdf
Health and Safety Executive. (n.d.). Material and priority scoring tools. Retrieved 12 March 2018, from Health and Safety Executive: http://www.hse.gov.uk/asbestos/assets/docs/materials-priority-scoring.pdf
Lenters, V., Burdorf, A., Vermeulen. R., Stayner, L., Heederik, D., (2012, October 1). Quality of evidence must guide risk assessment of asbestos. (B. O. Society, Ed.) The Annals of Occupational Hygiene, 56(8), 879-887. Retrieved 16 March 2018, from https://doi.org/10.1093/annhyg/mes065
Ministry of Business, Innovation and Employment. (2016). Health and Safety at Work (General Risk and Workplace Management) Regulations 2016. Retrieved 06 March 2018, from New Zealand Legislation: http://www.legislation.govt.nz/regulation/public/2016/0013/latest/DLM6727572.html
Ministry of Business, Innovation, and Employment. (2016). Health and Safety at Work (Asbestos) Regulations (2016). Retrieved 12 March 2018, from New Zealand Legislation: http://www.legislation.govt.nz/regulation/public/2016/0015/19.0/DLM6729706.html
New Zealand Government. (2015). Health and Safety at Work Act 2015. Retrieved 19 March 2018, from New Zealand Legislation: http://www.legislation.govt.nz/act/public/2015/0070/latest/DLM5976849.html
O’Neill, R. (2016, March). How the asbestos industry turns to British scientists. Hazards Magazine. Retrieved 16 March 2018, from http://www.hazards.org/asbestos/friendlyfibre.htm
Schüz, J., Schonfeld, S.J., Kromhout, H., Straif, K., Kashanskiy, S.V., Kovalevskiy, E.V., Bukhtiyarov, I.V., McCormack, V., (2013, August). A retrospective cohort study of cancer mortality in employees of a Russian chrysotile asbestos mine and mills: Study rationale and key features. Cancer Epidemiology, 37(4), pp. 440-445. Retrieved 15 March 2018, from https://doi.org/10.1016/j.canep.2013.03.001
The Mesothelioma Center. (n.d.). Asbestos-Related Conditions. Retrieved 15 March 2018, from Asbestos.com: https://www.asbestos.com/mesothelioma/related-diseases.php
WorkSafe New Zealand. (2016, October). Conducting asbestos surveys. Retrieved 12 March 2018, from WorkSafe: https://worksafe.govt.nz/topic-and-industry/asbestos/working-with-asbestos/conducting-asbestos-surveys/#lf-doc-25282
Yano, E., Wang, Z., Wang. X., Wang, M., Lan, Y., (2001, September 15). Cancer Mortality among Workers Exposed to Amphibole-free Chrysotile Asbestos. American Journal of Epidemiology, 154(6), 538-543. Retrieved 16 March 2018, from https://doi.org/10.1093/aje/154.6.538