# NIOSH Pocket Guide to Chemical Hazards
Methylal | CAS 109-87-5
CH3OCH2OCH3 | RTECS PA8750000
Synonyms & Trade Names Dimethoxymethane, Formal, Formaldehyde dimethylacetal, Methoxymethyl methyl ether, Methylene dimethyl ether | DOT ID & Guide 1234 127
Exposure Limits | NIOSH REL: TWA 1000 ppm (3100 mg/m3)
OSHA PEL: TWA 1000 ppm (3100 mg/m3)
IDLH 2200 ppm [10%LEL] | Conversion 1 ppm = 3.11 mg/m3
Physical Description Colorless liquid with a chloroform-like odor.
MW: 76.1 | BP: 111°F | FRZ: -157°F | Sol: 33%
VP: 330 mmHg | IP: 10.00 eV |  | Sp.Gr: 0.86
Fl.P(oc): -26°F | UEL: 13.8% | LEL: 2.2% |
Class IB Flammable Liquid: Fl.P. below 73°F and BP at or above 100°F.
Incompatibilities & Reactivities Strong oxidizers, acids
Measurement Methods NIOSH 1611
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: Water flush promptly Breathing: Respiratory support Swallow: Medical attention immediately
Respirator Recommendations NIOSH/OSHA Up to 2200 ppm: (APF = 10) Any supplied-air respirator/(APF = 50) Any self-contained breathing apparatus 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, ingestion, skin and/or eye contact
Symptoms Irritation eyes, skin, upper respiratory system; anesthesia
Target Organs Eyes, skin, respiratory system, central nervous system
See also: INTRODUCTION