Dutch Parliament Raises Concerns Over Asbestos Exposure Limits

in 2011 The Dutch Parliament has expressed concerns that the existing workplace asbestos exposure limits was not stringent enough, with the existing control limit set at 0.01 fibres per millilitre—ten times stricter than the United Kingdom's guidelines. Subsequently the EU has set the asbestos control limit to 0.01 fibres per millilitre across all member states from 2023.

Historically, policy formulation has relied on meta-analyses of numerous epidemiological studies. However, the Committee has identified flaws in this approach, noting that some studies do not accurately represent the actual exposures experienced by certain groups. This prompted a comprehensive review and a subsequent revised meta-analysis, leading to the exclusion of several studies deemed to provide misleading data.

The findings from this updated study are now considered the new benchmark for interpreting risks associated with asbestos exposure. Based on these results, the Committee has proposed significantly lower risk thresholds. Specifically, the maximum permissible risk level (analogous to the control limit) for amphiboles would be reduced from 0.01 f/ml to 0.0003 f/ml, and for chrysotile from 0.1 f/ml to 0.0028 f/ml.

Currently, the Dutch negligible risk level stands at 0.0001 f/ml for amphiboles and 0.001 f/ml for chrysotile. The proposed changes would see these levels lowered to 0.00028 f/ml for chrysotile and an even more stringent 0.000003 f/ml for amphiboles.

For context, the control limit in the UK is set at 0.1 f/ml. Thus, the Dutch proposals suggest a control limit that is 330 times lower. Additionally, while the UK does not define a negligible risk threshold for asbestos exposure, it uses a clearance indicator of 0.01 f/ml as a de facto benchmark. The Dutch proposal is dramatically lower, being 3,333 times less than the UK's indicator.

Despite the significant reductions proposed by the Dutch, the UK currently shows no inclination to amend its asbestos exposure limits. This stands in contrast to the proactive steps taken by the Dutch government, underscoring a significant divergence in public health policy approaches between the two countries.

Following this study, many academics have responded critisising the size of the cohorts subjected to the revised meta-analyses, potentially leading to an increased reporting of risk factors. In any case the Burdorf and Heederick report has stimulated some much needed discussion over occupational exposure limits for asbestos.

Note: For clarity within the UK context, the figures are expressed as fibres per millilitre, though the original report uses fibres per cubic meter.

Burdorf & Heederik. "Applying quality criteria to exposure in asbestos epidemiology increases the estimated risk." Ann Occup Hyg. 2011 Jul;55(6):565-8.

"Risks of environmental and occupational exposure." The Hague: Health Council of the Netherlands, 2010; publication no. 2010/10E. ISBN 978-90-5549-810-9.

Marcus Hill