NIOSH Pocket Guide to Chemical Hazards


CAS 75-43-4


RTECS PA8400000
Synonyms & Trade Names
Dichlorofluoromethane; Fluorodichloromethane; Freon® 21; Genetron® 21; Halon® 112; Refrigerant 21
DOT ID & Guide
1029 126


NIOSH REL: TWA 10 ppm (40 mg/m3)
OSHA PEL†: TWA 1000 ppm (4200 mg/m3)
IDLH 5000 ppm See: 75434 Conversion 1 ppm = 4.21 mg/m3
Physical Description
Colorless gas with a slight, ether-like odor. [Note: A liquid below 48°F. Shipped as a liquefied compressed gas.]
MW: 102.9
BP: 48°F
FRZ: -211°F
Sol(86°F): 0.7%
VP(70°F): 1.6 atm
IP: 12.39 eV
RGasD: 3.57

Fl.P: NA

Nonflammable Gas
Incompatibilities & Reactivities
Chemically-active metals such as sodium, potassium, calcium, powdered aluminum, zinc & magnesium; acid; acid fumes
Measurement Methods
NIOSH 2516
See: NMAM or OSHA Methods
Personal Protection & Sanitation (See protection)
Skin: Frostbite
Eyes: Frostbite
Wash skin: No recommendation
Remove: No recommendation
Change: No recommendation
Provide: Frostbite wash
First Aid (See procedures)
Eye: Frostbite
Skin: Frostbite
Breathing: Respiratory support

Important additional information about respirator selection
Respirator Recommendations NIOSH
Up to 100 ppm:
(APF = 10) Any supplied-air respirator
Up to 250 ppm:
(APF = 25) Any supplied-air respirator operated in a continuous-flow mode
Up to 500 ppm:
(APF = 50) Any self-contained breathing apparatus with a full facepiece
(APF = 50) Any supplied-air respirator with a full facepiece
Up to 5000 ppm:
(APF = 1000) Any supplied-air respirator 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
(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 and/or eye contact (liquid)
Symptoms Asphyxia, cardiac arrhythmias, cardiac arrest; liquid: frostbite
Target Organs respiratory system, cardiovascular system
See also: INTRODUCTION   See ICSC CARD: 1106