NIOSH Publication No. 2005-151:

NIOSH Pocket Guide to Chemical Hazards

September 2005

Methyl formate



Synonyms & Trade Names

Methyl ester of formic acid, Methyl methanoate
DOT ID & Guide
1243 / 129


NIOSH REL: TWA 100 ppm (250 mg/m3) ST 150 ppm (375 mg/m3)
OSHA PEL: TWA 100 ppm (250 mg/m3)
4500 ppm See: 107313
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 73F and BP below 100F.
Incompatibilities & Reactivities

Strong oxidizers [Note: Reacts slowly with water to form methanol & formic acid.]
Measurement Methods
NIOSH S291 (II-5); OSHA PV2041
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 (flammable)
Change: No recommendation

First Aid
(See procedures)
Eye: Irrigate immediately
Skin: Soap wash immediately
Breathing: Respiratory support
Swallow: Medical attention immediately
Respirator Recommendations
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
(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
Important additional information about respirator selection
Exposure Routes
inhalation, skin absorption, ingestion, skin and/or eye contact
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   See ICSC CARD: 0664