# NIOSH Pocket Guide to Chemical Hazards
Pentaborane | CAS 19624-22-7
B5H9 | RTECS RY8925000
Synonyms & Trade Names Pentaboron nonahydride | DOT ID & Guide 1380 135
Exposure Limits | NIOSH REL: TWA 0.005 ppm (0.01 mg/m3) ST 0.015 ppm (0.03 mg/m3)
OSHA PEL†: TWA 0.005 ppm (0.01 mg/m3)
IDLH 1 ppm | Conversion 1 ppm = 2.58 mg/m3
Physical Description Colorless liquid with a pungent odor like sour milk.
MW: 63.1 | BP: 140°F | FRZ: -52°F | Sol: Reacts
VP: 171 mmHg | IP: 9.90 eV |  | Sp.Gr: 0.62
Fl.P: 86°F | UEL: ? | LEL: 0.42% |
Class IC Flammable Liquid: Fl.P. at or above 73°F and below 100°F.
Incompatibilities & Reactivities Oxidizers, halogens, water, halogenated hydrocarbons [Note: May ignite SPONTANEOUSLY in moist air. Corrosive to natural rubber. Hydrolyzes slowly with heat in water to form boric acid.]
Measurement Methods None available
Personal Protection & Sanitation Skin: Prevent skin contact Eyes: Prevent eye contact Wash skin: When contaminated Remove: When wet (flammable) Change: No recommendation Provide: Eyewash, Quick drench | First Aid (See procedures) Eye: Irrigate immediately Skin: Soap wash immediately Breathing: Respiratory support Swallow: Medical attention immediately
Respirator Recommendations NIOSH/OSHA Up to 0.05 ppm: (APF = 10) Any supplied-air respirator Up to 0.125 ppm: (APF = 25) Any supplied-air respirator operated in a continuous-flow mode Up to 0.25 ppm: (APF = 50) Any supplied-air respirator that has a tight-fitting facepiece and is operated in a continuous-flow mode/(APF = 50) Any self-contained breathing apparatus with a full facepiece/(APF = 50) Any supplied-air respirator with a full facepiece Up to 1 ppm: (APF = 1000) Any supplied-air respirator 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 (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concern/Any appropriate escape-type, self-contained breathing apparatus
Exposure Routes inhalation, skin absorption, ingestion, skin and/or eye contact
Symptoms Irritation eyes, skin; dizziness, headache, drowsiness, incoordination, tremor, convulsions, behavioral changes; tonic spasm face, neck, abdominal, limbs
Target Organs Eyes, skin, central nervous system
See also: INTRODUCTION