NIOSH Pocket Guide to Chemical Hazards

Dimethyl sulfate

CAS 77-78-1


RTECS WS8225000
Synonyms & Trade Names
Dimethyl ester of sulfuric acid, Dimethylsulfate, Methyl sulfate
DOT ID & Guide
1595 156


NIOSH REL: Ca TWA 0.1 ppm (0.5 mg/m3) [skin] See Appendix A
OSHA PEL: TWA 1 ppm (5 mg/m3) [skin]
IDLH Ca [7 ppm] See: 77781 Conversion 1 ppm = 5.16 mg/m3
Physical Description
Colorless, oily liquid with a faint, onion-like odor.
MW: 126.1
BP: 370°F (Decomposes)
FRZ: -25°F
Sol(64°F): 3%
VP: 0.1 mmHg
IP: ?

Sp.Gr: 1.33
Fl.P: 182°F
UEL: ?
LEL: ?

Class IIIA Combustible Liquid: Fl.P. at or above 140F and below 200F.
Incompatibilities & Reactivities
Strong oxidizers, ammonia solutions [Note: Decomposes in water to sulfuric acid; corrosive to metals.]
Measurement Methods
NIOSH 2524
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: Water flush immediately
Breathing: Respiratory support
Swallow: Medical attention immediately
Important additional information about respirator selection
Respirator Recommendations 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 canister providing protection against the compound of concern/Any appropriate escape-type, self-contained breathing apparatus
Exposure Routes inhalation, skin absorption, ingestion, skin and/or eye contact
Symptoms Irritation eyes, nose; headache; dizziness; conjunctivitis; photophobia (abnormal visual intolerance to light); periorbital (situated around the eye) edema; dysphonia, aphonia, dysphagia, productive cough; chest pain; dyspnea (breathing difficulty), cyanosis; vomiting, diarrhea; dysuria; analgesia; fever; proteinuria, hematuria (blood in the urine); eye, skin burns; delirium; [potential occupational carcinogen]
Target Organs Eyes, skin, respiratory system, liver, kidneys, central nervous system

Cancer Site [in animals: nasal & lung cancer]
See also: INTRODUCTION   See ICSC CARD: 0148   See MEDICAL TESTS: 0084