Asbestos exposure and risk in Britain today

Keynote talk at the Conference Asbestos 2025. It discusses current exposure to asbestos and the priorities for dealing with the asbestos legacy in Britain.

1. How did we get here and where should we go next? John Cherrie

2. Summary… What happened? Where are people now exposed to asbestos? Occupational asbestos exposures were very high in the past, but that’s not the case today Respirators can be very effective at reducing exposure Exposure data can be used to estimate disease burden

3. My early career

4. synthetic My involvement with mineral fibres …

5. Exposure measurement… Importance of graticule size in fibre counting Laboratory quality assurance schemes Measurement of exposure, including simulations Modelling past exposure Cherrie J. (1984) The effect of microscope graticule size and counting rules on the estimation of airborne fibre numbers using the membrane filter technique. Annals of Occupational Hygiene; 28: 229-36. Ogden TL, Shenton-Taylor T, Cherrie JW, Crawford NP, Moorcroft S, Duggan MJ, Jackson PA, Treble RD. (1986) Within-laboratory quality control of asbestos counting. Ann Occup Hyg ; 30: 411-25. Cherrie J, Krantz S, Schneider T, Ohberg I, Kamstrup O, Linander W. (1987) An experimental simulation of an early rock wool/slag wool production process. The Annals of Occupational Hygiene; 31: 583-93. Dodgson J, Cherrie J, Groat S. (1987) Estimates of past exposure to respirable man-made mineral fibres in the European insulation wool industry. The Annals of Occupational Hygiene; 31: 567-82.

6. Modelling exposure… E = Substance emission potential H = Active emission potential LC = Local controls ta = time source active Su = passive emissions D = Dilution ventilation RPE = effect of respirators Cherrie JW, McElvenny D, Blyth KG. (2018) Estimating past inhalation exposure to asbestos: A tool for risk attribution and disease screening. Int J Hyg Environ Health; 221: 27-32.   Near-field Far-field

7. Modelling asbestos exposure…

8. Lung cancer case-control study… Kjærheim K, Boffetta P, Hansen J, Cherrie J, Chang-Claude J, Eilber U, Ferro G, Guldner K, Olsen JH, Plato N, et al. (2002) Lung cancer among rock and slag wool production workers. Epidemiology; 13: 445-53. Cherrie J, Schneider T. (1999) Validation of a new method for structured subjective assessment of past concentrations. The Annals of Occupational Hygiene; 43: 235-45. Synthetic mineral fibre workers

9. Asbestos in the past

10. The bad old days…

11. IOM data from the 1990s Howie , R. et al (1996). Workplace effectiveness of respiratory protective equipment for asbestos removal work (No. HSE CRR 112:90. ). HSE.

12. Asbestos burden estimate… As part of a comprehensive assessment of occupational cancer burden in GB in 2004 Used a simplistic approach, assuming there was one lung cancer for each mesothelioma Gave an estimate of around 4,000 deaths per year Around 9% of lung cancer deaths in men attributed to asbestos Rushton L, Hutchings SJ, Fortunato L, Young C, Evans GS, Brown T, Bevan R, Slack R, Holmes P, Bagga S, et al. (2012) Occupational cancer burden in Great Britain. British Journal of Cancer; 107: S3-S7.

13. Asbestos today

14. Where are people likely to be exposed? Removing ACMs Being in the vicinity of removal works or after works complete Inadvertently disturbing ACMs in buildings, e.g. maintenance workers, firefighters etc. Working or being in buildings containing ACMs, e.g. teachers Working on contaminated land Community exposure from industrial fires or storm damaged buildings with ACM

15. Removal work in Britain… Barrowcliffe D, Saunders M. (2024) The use of control measures during licensed asbestos removal. HSE report RR1217. PCOM data

16. Remediation work in Denmark… Brostrøm A, Harboe H, Fonseca AS, Frederiksen M, Kines P, Bührmann W, Bønløkke JH, Jensen KA. (2025) Asbestos fiber levels from remediation work. Journal of Hazardous Materials Advances; 17. Worker breathing zone SEM data 8-hr average

17. Plumbers in Britain… Burdett G, Bard D. (2007) Exposure of UK industrial plumbers to asbestos, Part I: Monitoring of exposure using personal passive samplers. The Annals of Occupational Hygiene; 51: 121-30. Average 0.058 fibres /ml

18. Samples taken outside enclosure… TEM data Average <0.0025 f/ml Barrowcliffe D, Davies L. (2022) Asbestos exposures to workers in the licensed asbestos removal industry. HSE report RR1176.

19. In schools and office buildings… Average concentrations measured in occupied classrooms in England after remediation <0.00005 f/ml  Occupied office in England before remediation 0.00002 f/ml US asbestos containing schools 0.0001 f/ml US buildings 0.00008 f/ml Nearby outdoor 0.00002 f/ml Burdett G, Cottrell S, Taylor C. (2009) Airborne fibre and asbestos concentrations in system built schools. Journal of Physics: Conference Series; 151.

20. Oil refinery workers in the USA… Data from t hree US Gulf Coast refinery and petrochemical complexes for people working around undisturbed legacy ACM in open-air environments 157 samples analysed by PCOM, 75 were > LoD   When analysed by TEM the asbestos concentrations were < LoD Ninety-fifth percentile upper confidence intervals for exposure groups ranged from 0.0012 to 0.00019 fibres/ml Malek L, Tutt R, Altom D, Lacey S. (2025) Evaluating asbestos exposures of occupational non-users at three refinery and petrochemical complexes using the U.S. EPA draft existing chemical occupational exposure value for asbestos. J Occup Environ Hyg ; 1-4.

21. Contaminated land… There may be around 10k sites and 100k people exposed There is no good data on the levels of exposure, but these are likely to be on average low Hellawell EE, Hughes SJ. (2021) Asbestos contamination on brownfield development sites in the UK. Environ Res; 198: 110480.

22. Contaminated land… Jones et al. (2010) Laboratory Tests to Compare Airborne Respirable Mass and Fibre Concentrations from Soil Samples from Libby, Montana. Indoor and Built Environment; 19: 286-97.

23. Respirators reduce exposure… Howie , R. et al (1996). Workplace effectiveness of respiratory protective equipment for asbestos removal work. HSE CRR 112:90. Median PF = 1250

24. Exposure is more than the level in the air… If we want to assess the population risk, then we also need information about: Number of people exposed Number of days exposed each year Number of years exposed This data can be used to estimate disease burden, i.e. the number of cases of disease that could occur in a period We’d also need other information, e.g. the age and sex distribution

25. Weighting analysis…

26. …and the future

27. What do we hope for? ?

28. Cancer burden… A new cancer burden estimate would allow an assessment of current burden …and future burden We just need estimates like those used in the weighting analysis Burden estimates also let you explore alternative futures

29. Group Number exposed Exposure level (f/ml) Hours per year (fraction) Years Weighting Summed weighting Working or being in buildings containing ACMs, e.g. teachers 15,000,000 0.00005 1 60 45,000 Inadvertently disturbing ACMs in buildings, e.g. maintenance workers, firefighters etc. 300,000 0.005 0.1 20 3000 48,000               Removing ACMs wearing respirator 20,000 0.0001 1 10 20   Being in the vicinity of removal works or after works complete 15,000,000 0.002 0.05 1 1,500   In the year after removal works 15,000,000 0.0005 0.95 1 7,125   The buildings that are awaiting removal 15,000,000 0.00005 1 20 15,000 23,625 What should we do about the legacy?

30. Conclusions… Exposure levels are probably very low Information about exposure is limited and mostly poor quality, particularly in relation to the number of people at risk Priority areas can be identified A proper disease burden assessment is feasible and could help inform priorities