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The fibrogenicity and carcinogenicity of asbestos fibers are dependent on several fiber parameters including fiber dimensions. Based on the WHO (World Health Organization) definition, the current regulations focalise on long asbestos fibers (LAF) (Length: L ≥ 5 μm, Diameter: D < 3 μm and L/D ratio > 3). However air samples contain short asbestos fibers (SAF) (L < 5 μm). In a recent study we found that several air samples collected in buildings with asbestos containing materials (ACM) were composed only of SAF, sometimes in a concentration of ≥10 fibers.L−1. This exhaustive review focuses on available information from peer-review publications on the size-dependent pathogenetic effects of asbestos fibers reported in experimental in vivo and in vitro studies. In the literature, the findings that SAF are less pathogenic than LAF are based on experiments where a cut-off of 5 μm was generally made to differentiate short from long asbestos fibers. Nevertheless, the value of 5 μm as the limit for length is not based on scientific evidence, but is a limit for comparative analyses. From this review, it is clear that the pathogenicity of SAF cannot be completely ruled out, especially in high exposure situations. Therefore, the presence of SAF in air samples appears as an indicator of the degradation of ACM and inclusion of their systematic search should be considered in the regulation. Measurement of these fibers in air samples will then make it possible to identify pollution and anticipate health risk.

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Amphibole asbestos is present in the Salau massif. Its composition varies from ferro-actinolite to actinolite. Asbestos is found in post-Hercynian slip-dip faults and crack-seal veins, which are compatible in the Pyrenees with Mesozoic hydrothermal events. The amount of asbestos contained in the faults is sufficient to explain the levels of asbestos dust measured during the former mining activity. According to different sources, the number of employees in the Salau mine varied from 150 to 600. Between 1982 and 1991, analyses were performed on sputum and/or bronchoalveolar washes on 28 patients. In 13 of these patients, the results showed significant retention of asbestos bodies, with concentrations equal to or higher than the values generally used as a reference in Europe. The occupational exposure limit of 8 hours (OEL8hours) could be estimated for each workstation. Estimates were based in part on phase contrast microscopy (PCM) measurements. Simultaneous measurements by PCM and transmission electron microscopy (TEM) allowed for a correction. The estimated OEL8hours have a unimodal distribution with an average of 0.05 actinolite fibers/cm3. The highest measurements (3.4%) were between 0.178 and 0.282 actinolite fibers/cm3. These occurred at the crusher and drilling sites of the work area. These results differ from those obtained in 2019 during the safety and sampling operations for asbestos detection before a drilling campaign, for which the company was supposed to take the asbestos hazard into account in its risk analysis. No asbestos fibers were observed, with TEM measurements, during the most emissive activities. Concentrations were less than 0.0048 fibers/cm3.