NIOSH Publication No. 2005-151:

NIOSH Pocket Guide to Chemical Hazards

September 2005

Methylene chloride



Synonyms & Trade Names

Dichloromethane, Methylene dichloride
DOT ID & Guide
1593 / 160


NIOSH REL: Ca See Appendix A
OSHA PEL: [1910.1052] TWA 25 ppm ST 125 ppm
Ca [2300 ppm] See: 75092
1 ppm = 3.47 mg/m3
Physical Description
Colorless liquid with a chloroform-like odor. [Note: A gas above 104°F.]
MW: 84.9
BP: 104°F
FRZ: -139°F
Sol: 2%
VP: 350 mmHg
IP: 11.32 eV

Sp.Gr: 1.33
Fl.P: ?
UEL: 23%
LEL: 13%

Combustible Liquid
Incompatibilities & Reactivities

Strong oxidizers; caustics; chemically-active metals such as aluminum, magnesium powders, potassium & sodium; concentrated nitric acid
Measurement Methods
NIOSH 1005, 3800; OSHA 80
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 or contaminated
Change: No recommendation
Provide: Eyewash, Quick drench
First Aid
(See procedures)
Eye: Irrigate immediately
Skin: Soap wash promptly
Breathing: Respiratory support
Swallow: Medical attention immediately
Respirator Recommendations
(See Appendix E) NIOSH
At concentrations above the NIOSH REL, or where there is no REL, at any detectable concentration:
(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, skin; lassitude (weakness, exhaustion), drowsiness, dizziness; numbness, tingle limbs; nausea; [potential occupational carcinogen]
Target Organs
Eyes, skin, cardiovascular system, central nervous system

Cancer Site
[in animals: lung, liver, salivary & mammary gland tumors]
See also: INTRODUCTION   See ICSC CARD: 0058   See MEDICAL TESTS: 0148