Commercial brucite, a worldwide used raw material deemed safe, can be contaminated by asbestos

Brucite is a raw material used in several applications and worldwide traded. The main active deposits are located in North America, North Europe and China and the extracted material is worked and delivered all over the world without any particular precaution as it is considered a safe inert product. But is it really true? Applying a consolidated protocol of analysis for the detection and characterization of fibers, we found asbestos in a sample of commercial brucite. The analyzed material is primarily composed of plate-like crystals of brucite; nevertheless, chemical and mineralogical analyses revealed the presence of serpentine, while morphometric observation through electron microscopy confirmed the occurrence of respirable regulated chrysotile (serpentine asbestos) fibers. The individual fibers making up the chrysotile bundles have length >5 µm, width <3 µm, length/width ratio >3, and their concentration in the investigated product is 169 mg/kg (0.02 wt%). Although paragenesis of brucite with chrysotile has been known for a long time, never before was documented a commercial brucite, distributed worldwide, contaminated with asbestos. In the light of these results, we think that certification of the absence of asbestos should be imposed to the brucite mining companies and distributors; otherwise, users should always include a careful inspection on incoming materials, at least by electron microscopy, to rule out the occurrence of asbestos.