NIOSH Publication No. 2005-151:

NIOSH Pocket Guide to Chemical Hazards

September 2005

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] See: 109875
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 73F and BP at or above 100F.
Incompatibilities & Reactivities

Strong oxidizers, acids
Measurement Methods
NIOSH 1611
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: 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
Important additional information about respirator selection
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   See ICSC CARD: 1152