Synonym: amorphous boron

OSHA IMIS Code Number: B142

Chemical Abstracts Service (CAS) Registry Number: 7440-42-8

NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: ED4550000

Chemical Description and Physical Properties:

odorless, black, hard, solid; brown amorphous powder; crystals
element: B
molecular weight: 10.81

Incompatibilities: Avoid storing with fluorine, chlorine, bromine, iodine, ammonia, nitric acid, sulfur, hydrogen iodide and oxidizing agents.

Notes:

1. Elemental boron does not exist naturally.
   Occupational exposure to boron is mostly through inhalation of dust during the mining and subsequent processing of borate-containing minerals (e.g., borax, colemanite, boracite, kernite, and ulexite).
2. EPA's oral reference dose (daily oral exposure likely to be without an appreciable risk of deleterious effects during a lifetime) of boron is 0.2 mg/kg/day (based mainly on animal studies with boric acid).
3. Although some animal data indicate boron to be an essential element with unknown biochemical mechanism, human requirement of boron as a micronutrient has not been conclusively established.
4. The California Department of Health Services established a notification level for boron of 1 milligram per liter of drinking water.

Date Last Revised: 12/02/2005

Literature Basis:

• California Department of Health Services-Drinking Water Program: Drinking Water Notification Levels, 2005.
• U.S. EPA Integrated Risk Information System: Toxicological Review of Boron and Compounds (CAS 7440-42-8), 2004 (EPA 635/04/052).
• Panel on Micronutrients, et al.: Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, D.C.: The National Academies Press, 2000, 800 pp.
• Pohanish, R.P. (editor): Boron, Boric Acid and Borax. In, Sittig's Handbook of Toxic and Hazardous Chemicals and Carcinogens, Fourth Ed., Vol. 1. Norwich, NY: Noyes Publications, William Andrew Publishing, 2002, pp. 355-357.

Primary Laboratory Sampling/Analytical Method (SLC1):

• note: See Particulates not otherwise regulated (Total Dust)
  note: See Particulates not otherwise regulated (Respirable Fraction)

Wipe sampling:

• sampling media: Whatman smear tab
  analytical solvent: Deionized water
  

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