Asbestos Fiber

Asbestos Fiber HSN : 25249021

CAS: 1332-21-4. A group of impure
magnesium silicate minerals which occur in fib- rous form. Colors: white, gray, green, brown. D 2.5. Noncombustible.
(1) Serpentine asbestos is the mineral chryso- tile, a magnesium silicate. The fibers are strong and flexible so that spinning is possible with the longer fibers. A microcrystalline form, TM "Avi- best," has been developed.
(2) Amphibole asbestos includes various sili- cates of magnesium, iron, calcium and sodium. The fibers are generally brittle and cannot be spun, but are more resistant to chemicals and to heat than serpentine asbestos.
(3) Amosite.
(4) Crocidolite.

Occurrence: Vermont, Arizona, California, North Carolina, Africa, Italy, Yukon, Quebec, Mexico, Hazard: A carcinogen. Highly toxic by inhalation of dust particles. TLV (amosite) 0.5 fibers/cc more than 5 microns long; (chrysotile) 2 fibers/ cc more than 5 microns long; (crocidolite) 0.2 fibers/cc more than 5 microns long; (other forms) 2 fibers/cc more than 5 microns long. Use: Fireproof fabrics, brake lining, gaskets, roof- ing compositions, electrical and heat insulations, paint filler, chemical filters, reinforcing agent in rubber and plastics, component of paper dryer felts, diaphragm cells, cement reinforcement.

Note: A promising substitute for asbestos for ce- ment reinforcement is glass fiber made from slate and limestone.