SI-TUFF™ is made from a fibrous form of single-crystal silicon carbide, known as "whiskers". From an OSHA and ECHA standpoint, they are classified as non-hazardous. They have no extractables and are non-bioactive. They are CFR-21 complient for indirect food contact applications. However, the dry materials are dusty. Since they are in the respirable size range, they may be considered hazardous at chronic exposure levels. This only applies in dry powder form - if supplied wet such as in aqueous dispersion, SI-TUFF™ is non-respirable and non-hazardous.
If you work with SI-TUFF™ in dry powder form, you should take appropriate measures to ensure safety. Luckily, this is neither difficult nor expensive to do. If airborne concentrations exceed the recommended limits by ACGIH® TLV® (0.1 fibers/cc TWA, respirable fibers), a suitable respirator should be worn in accordance with OSHA's Respiratory Protection Standard (29 CFR § 1910). Handle whiskers in a fashion whereby they do not become airborne during any stage of processing. It is recommended to also install suction equipment where dry powder transfer occurs.
While not classified by OSHA or NTP as a carcinogen, IARC classifies the family of ceramic fibers, which includes silicon carbide whiskers, as group 2B: possibly carcinogenic to humans (group 2B: "There is sufficient evidence for the carcinogenicity of ceramic fibers in experimental animals; no data were available on the carcinogenicity of ceramic fibers to humans"). ACGIH® has classified silicon carbide whiskers as A2: Suspected Human Carcinogen ("The carcinogen designation of A2; Suspected Human Carcinogen, is recommended for fibrous forms, based on inhalation experiments in several species showing lung and pleural carcinogenicity, and limited human data for lung cancer").
For additional information, please refer to the appropriate SDS located on the Resources Page.