NIOSH Pocket Guide to Chemical Hazards

Hexamethyl phosphoramide

CAS 680-31-9


RTECS TD0875000
Synonyms & Trade Names
Hexamethylphosphoric triamide, Hexamethylphosphorotriamide, HMPA, Tris(dimethylamino)phosphine oxide
DOT ID & Guide


NIOSH REL: Ca See Appendix A
OSHA PEL: none
IDLH Ca [N.D.] See: IDLH INDEX Conversion
Physical Description
Clear, colorless liquid with an aromatic or mild, amine-like odor. [Note: A solid below 43°F.]
MW: 179.2
BP: 451°F
FRZ: 43°F
Sol: Miscible
VP: 0.03 mmHg
IP: ?

Sp.Gr: 1.03
Fl.P: 220°F
UEL: ?
LEL: ?

Class IIIB Combustible Liquid: Fl.P. at or above 200F.
Incompatibilities & Reactivities
Oxidizers, strong acids, chemically-active metals (e.g., potassium, sodium, magnesium, zinc)
Measurement Methods
None available
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 organic vapor canister/Any appropriate escape-type, self-contained breathing apparatus
Exposure Routes inhalation, skin absorption, ingestion, skin and/or eye contact
Symptoms Irritation eyes, skin, respiratory system; dyspnea (breathing difficulty); abdominal pain; [potential occupational carcinogen]
Target Organs Eyes, skin, respiratory system, central nervous system, gastrointestinal tract

Cancer Site [in animals: cancer of the nasal cavity]
See also: INTRODUCTION   See ICSC CARD: 0162