In France, the present regulations on occupational exposure to asbestos fibers take into account fibers (FRp: fibers measured for industrial hygiene) with the following dimensions: L > 5 μm, D 3 where L is the length and D the diameter of the fiber. The limit value is set at 0.1 f/cm3 for 1 hr. By definition short asbestos fibers (SAFs) are the fibers with 0.5 μm < L< 5 μm, D < 3 μm, and L/D ≥ 3; thin asbestos fibers (TAFs) are the fibers with L ≥ 5 μm, D < 0.2 μm, and L/D ≥ 3. The aim assigned to the French Agency for Environmental and Occupational Health Safety (AFSSET) Occupational Exposure Limit (OEL) Committee, was essentially to evaluate the following elements: the relevance of the present French OEL, knowing that this limit excludes the counting of SAFs and TAFs; the consistency of the OEL in light of the different varieties of asbestos by studying possible differential toxicity according to the type of asbestos (chrysotile vs. amphiboles); and the assessment of different measurin...