# NIOSH Pocket Guide to Chemical Hazards
n-Butyl mercaptan | CAS 109-79-5
CH3CH2CH2CH2SH | RTECS EK6300000
Synonyms & Trade Names Butanethiol, 1-Butanethiol, n-Butanethiol, 1-Mercaptobutane | DOT ID & Guide 2347 130
Exposure Limits | NIOSH REL: C 0.5 ppm (1.8 mg/m3) [15-minute]
OSHA PEL†: TWA 10 ppm (35 mg/m3)
IDLH 500 ppm | Conversion 1 ppm = 3.69 mg/m3
Physical Description Colorless liquid with a strong, garlic-, cabbage-, or skunk-like odor.
MW: 90.2 | BP: 209°F | FRZ: -176°F | Sol: 0.06%
VP: 35 mmHg | IP: 9.15 eV |  | Sp.Gr: 0.83
Fl.P: 35°F | UEL: ? | LEL: ? |
Class IB Flammable Liquid: Fl.P. below 73°F and BP at or above 100°F.
Incompatibilities & Reactivities Strong oxidizers (such as dry bleaches), acids
Measurement Methods NIOSH 2525, 2542
Personal Protection & Sanitation Skin: Prevent skin contact Eyes: Prevent eye contact Wash skin: When contaminated Remove: When wet (flammable) Change: No recommendation | First Aid (See procedures) Eye: Irrigate immediately Skin: Soap wash promptly Breathing: Respiratory support Swallow: Medical attention immediately
Respirator Recommendations NIOSH Up to 5 ppm: (APF = 10) Any chemical cartridge respirator with organic vapor cartridge(s)/(APF = 10) Any supplied-air respirator Up to 12.5 ppm: (APF = 25) Any supplied-air respirator operated in a continuous-flow mode/(APF = 25) Any powered, air-purifying respirator with organic vapor cartridge(s) Up to 25 ppm: (APF = 50) Any chemical cartridge respirator with a full facepiece and organic vapor cartridge(s)/(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister/(APF = 50) Any powered, air-purifying respirator with a tight-fitting facepiece and organic vapor cartridge(s)/(APF = 50) Any self-contained breathing apparatus with a full facepiece/(APF = 50) Any supplied-air respirator with a full facepiece Up to 500 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 organic vapor canister/Any appropriate escape-type, self-contained breathing apparatus
Exposure Routes inhalation, ingestion, skin and/or eye contact
Symptoms Irritation eyes, skin; muscle weakness, malaise (vague feeling of discomfort), sweating, nausea, vomiting, headache, confusion; in animals: narcosis, incoordination, lassitude (weakness, exhaustion); cyanosis, pulmonary irritation; liver, kidney damage
Target Organs Eyes, skin, respiratory system, central nervous system, liver, kidneys
See also: INTRODUCTION