# NIOSH Pocket Guide to Chemical Hazards
Methyl formate | CAS 107-31-3
HCOOCH3 | RTECS LQ8925000
Synonyms & Trade Names Methyl ester of formic acid, Methyl methanoate | DOT ID & Guide 1243 129
Exposure Limits | NIOSH REL: TWA 100 ppm (250 mg/m3) ST 150 ppm (375 mg/m3)
OSHA PEL†: TWA 100 ppm (250 mg/m3)
IDLH 4500 ppm | Conversion 1 ppm = 2.46 mg/m3
Physical Description Colorless liquid with a pleasant odor. [Note: A gas above 89°F.]
MW: 60.1 | BP: 89°F | FRZ: -148°F | Sol: 30%
VP: 476 mmHg | IP: 10.82 eV |  | Sp.Gr: 0.98
Fl.P: -2°F | UEL: 23% | LEL: 4.5% |
Class IA Flammable Liquid: Fl.P. below 73°F and BP below 100°F.
Incompatibilities & Reactivities Strong oxidizers [Note: Reacts slowly with water to form methanol & formic acid.]
Measurement Methods NIOSH S291 (II-5); OSHA PV2041
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 immediately Breathing: Respiratory support Swallow: Medical attention immediately
Respirator Recommendations NIOSH/OSHA Up to 1000 ppm: (APF = 10) Any supplied-air respirator* Up to 2500 ppm: (APF = 25) Any supplied-air respirator operated in a continuous-flow mode* Up to 4500 ppm: (APF = 50) Any self-contained breathing apparatus with a full facepiece/(APF = 50) Any supplied-air respirator with a full facepiece 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, skin absorption, ingestion, skin and/or eye contact
Symptoms Irritation eyes, nose; chest tightness, dyspnea (breathing difficulty); visual disturbance; central nervous system depression; in animals: pulmonary edema; narcosis
Target Organs Eyes, respiratory system, central nervous system
See also: INTRODUCTION