# NIOSH Pocket Guide to Chemical Hazards
Methylene bis(4-cyclohexylisocyanate) | CAS 5124-30-1
CH2[(C6H10)NCO]2 | RTECS NQ9250000
Synonyms & Trade Names Dicyclohexylmethane 4,4'-diisocyanate; DMDI; bis(4-Isocyanatocyclohexyl)methane; HMDI; Hydrogenated MDI; Reduced MDI; Saturated MDI | DOT ID & Guide
Exposure Limits | NIOSH REL: C 0.01 ppm (0.11 mg/m3)
OSHA PEL†: none
IDLH N.D. | Conversion 1 ppm = 10.73 mg/m3
Physical Description Clear, colorless to light-yellow liquid.
MW: 262.4 | BP: ? | FRZ: <14°F | Sol: Reacts
VP(77°F): 0.001 mmHg | IP: ? |  | Sp.Gr(77°F): 1.07
Fl.P: >395°F | UEL: ? | LEL: ? |
Class IIIB Combustible Liquid: Fl.P. at or above 200°F.
Incompatibilities & Reactivities Water, ethanol, alcohols, amines, bases, acids, organotin catalysts [Note: May slowly polymerize if heated above 122°F.]
Measurement Methods None available
Personal Protection & Sanitation Skin: Prevent skin contact Eyes: Prevent eye contact Wash skin: When contaminated Remove: When wet or contaminated Change: No recommendation Provide: Quick drench | First Aid (See procedures) Eye: Irrigate immediately Skin: Water flush immediately Breathing: Respiratory support Swallow: Medical attention immediately
Respirator Recommendations NIOSH Up to 0.1 ppm: (APF = 10) Any supplied-air respirator* Up to 0.25 ppm: (APF = 25) Any supplied-air respirator operated in a continuous-flow mode* Up to 0.5 ppm: (APF = 50) Any self-contained breathing apparatus with a full facepiece/(APF = 50) Any supplied-air respirator with a full facepiece Up to 1 ppm: (APF = 2000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode 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, respiratory system; skin, respiratory sensitization; chest tightness, dyspnea (breathing difficulty), cough, dry throat, wheezing, pulmonary edema; skin blisters
Target Organs Eyes, skin, respiratory system
See also: INTRODUCTION