Silica exists in crystalline and amorphous forms. Crystalline forms are a health hazard, if the particles are small enough. Fortunately for chromatographers and column packers, silica in HPLC columns is amorphous (noncrystalline) silica gel.
On June 23, 2018, OSHA issued standards limiting exposure of workers to respirable crystalline silica (RCS). If exposure exceeds 50 µg/m3, the employer must provide protective equipment.1
The OSHA website reports:
“Crystalline silica is a common mineral found in many naturally occurring materials and used in many industrial products and at construction sites. Materials like sand, concrete, stone, and mortar contain crystalline silica. Crystalline silica is also used to make products such as glass, pottery, ceramics, bricks, concrete, and artificial stone. Industrial sand used in certain operations, such as foundry work and hydraulic fracturing (fracking), is also a source of crystalline silica exposure. Amorphous silica, such as silica gel, is not crystalline silica.”2
I anticipate that some associates may ask about the exposure rules on silica in chromatography columns. The primary reference is Ref. 1 below, and the secondary but most reassuring reference is Ref 2.
References
- https://www.federalregister.gov/documents/2016/03/25/2016-04800/occupational-exposure-to-respirable-crystalline-silica
- https://www.osha.gov/dsg/topics/silicacrystalline/background_info_silica.html
Robert L. Stevenson, Ph.D., is Editor Emeritus, American Laboratory/Labcompare; e-mail: [email protected]
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