NIOSH Publication No. 2005-151:

NIOSH Pocket Guide to Chemical Hazards

September 2005

Boron oxide

CAS
1303-86-2

B2O3

RTECS
ED7900000
Synonyms & Trade Names

Boric anhydride, Boric oxide, Boron trioxide
DOT ID & Guide

Exposure
Limits

NIOSH REL: TWA 10 mg/m3
OSHA PEL: TWA 15 mg/m3
IDLH
2000 mg/m3 See: 1303862
Conversion
Physical Description
Colorless, semitransparent lumps or hard, white, odorless crystals.
MW: 69.6
BP: 3380°F
MLT: 842°F
Sol: 3%
VP: 0 mmHg (approx)
IP: 13.50 eV

Sp.Gr: 2.46
Fl.P: NA
UEL: NA
LEL: NA

Noncombustible Solid
Incompatibilities & Reactivities

Water [Note: Reacts slowly with water to form boric acid.]
Measurement Methods
NIOSH 0500
See: NMAM or OSHA Methods
Personal Protection & Sanitation
(See protection)
Skin: Prevent skin contact
Eyes: Prevent eye contact
Wash skin: When contaminated
Remove: When wet or contaminated
Change: No recommendation

First Aid
(See procedures)
Eye: Irrigate immediately
Skin: Water flush promptly
Breathing: Fresh air
Swallow: Medical attention immediately
Respirator Recommendations
NIOSH
Up to 50 mg/m3:
(APF = 5) Any quarter-mask respirator. Click here for information on selection of N, R, or P filters.*
Up to 100 mg/m3:
(APF = 10) Any particulate respirator equipped with an N95, R95, or P95 filter (including N95, R95, and P95 filtering facepieces) except quarter-mask respirators. The following filters may also be used: N99, R99, P99, N100, R100, P100. Click here for information on selection of N, R, or P filters.*
(APF = 10) Any supplied-air respirator*
Up to 250 mg/m3:
(APF = 25) Any supplied-air respirator operated in a continuous-flow mode*
(APF = 25) Any powered air-purifying respirator with a high-efficiency particulate filter.*
Up to 500 mg/m3:
(APF = 50) Any air-purifying, full-facepiece respirator with an N100, R100, or P100 filter. Click here for information on selection of N, R, or P filters.
(APF = 50) Any powered, air-purifying respirator with a tight-fitting facepiece and a high-efficiency particulate filter*
(APF = 50) Any self-contained breathing apparatus with a full facepiece
(APF = 50) Any supplied-air respirator with a full facepiece
Up to 2000 mg/m3:
(APF = 2000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
Emergency or planned entry into unknown concentrations or IDLH conditions:
(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus
Escape:
(APF = 50) Any air-purifying, full-facepiece respirator with an N100, R100, or P100 filter. Click here for information on selection of N, R, or P filters./Any appropriate escape-type, self-contained breathing apparatus
Important additional information about respirator selection
Exposure Routes
inhalation, ingestion, skin and/or eye contact
Symptoms
Irritation eyes, skin, respiratory system; cough; conjunctivitis; skin erythema (skin redness)
Target Organs
Eyes, skin, respiratory system
See also: INTRODUCTION   See ICSC CARD: 0836