Potential Problems with Determining Elongate Mineral Particle (EMP) Potency (Comments on article entitled, "A Comparison of Asbestos Fiber Potency and Elongate Mineral Particle (EMP) Potency for Mesothelioma in Humans").

•Fiber potency for mesothelioma has been done using case numbers and exposure data.•Exposure data for fibers is often sparse prior to the 1970s.•Not all fibers have the same toxicology and not all are mesotheliogenic.•Fiber potency may be misleading without accurate measurement and toxicology data.