NIOSH Pocket Guide to Chemical Hazards

Hafnium CAS 7440-58-6
Hf RTECS MG4600000
Synonyms & Trade Names
Celtium, Elemental hafnium, Hafnium metal
DOT ID & Guide
1326 170 (powder, wet)
2545 135 (powder, dry)
Exposure
Limits
NIOSH REL*: TWA 0.5 mg/m3 [*Note: The REL also applies to other hafnium compounds (as Hf).]
OSHA PEL*: TWA 0.5 mg/m3 [*Note: The PEL also applies to other hafnium compounds (as Hf).]
IDLH 50 mg/m3 (as Hf) Conversion
Physical Description
Highly lustrous, ductile, grayish solid.
MW: 178.5
BP: 8316°F
MLT: 4041°F
Sol: Insoluble
VP: 0 mmHg (approx)
IP: NA

Sp.Gr: 13.31
Fl.P: NA
UEL: NA
LEL: NA

Explosive in powder form (either dry or with <25% water); finely divided powder can be ignited by static electricity or even SPONTANEOUSLY.
Incompatibilities & Reactivities
Strong oxidizers, chlorine
Measurement Methods
NIOSH S194 (II-5); OSHA ID121
Personal Protection & Sanitation
Skin: Prevent skin contact
Eyes: Prevent eye contact
Wash skin: When contaminated/Daily
Remove: When wet or contaminated
Change: Daily
Provide: Eyewash, Quick drench
First Aid (See procedures)
Eye: Irrigate immediately
Skin: Soap wash promptly
Breathing: Respiratory support
Swallow: Medical attention immediately
Respirator Recommendations NIOSH/OSHA
Up to 2.5 mg/m3: (APF = 5) Any dust and mist respirator
Up to 5 mg/m3: (APF = 10) Any dust and mist respirator except single-use and quarter-mask respirators/(APF = 10) Any supplied-air respirator
Up to 12.5 mg/m3: (APF = 25) Any supplied-air respirator operated in a continuous-flow mode*/(APF = 25) Any powered, air-purifying respirator with a dust and mist filter*
Up to 25 mg/m3: (APF = 50) Any air-purifying, full-facepiece respirator with a high-efficiency particulate filter/(APF = 50) Any supplied-air respirator that has a tight-fitting facepiece and is operated in a continuous-flow mode*/(APF = 50) Any powered, air-purifying respirator with a tight-fitting facepiece and a high-efficiency particulate filter*/(APF = 50) Any self-contained breathing apparatus with a full facepiece/(APF = 50) Any supplied-air respirator with a full facepiece
Up to 50 mg/m3: (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 with a high-efficiency particulate filter/Any appropriate escape-type, self-contained breathing apparatus
Exposure Routes inhalation, ingestion, skin and/or eye contact
Symptoms In animals: irritation eyes, skin, mucous membrane; liver damage
Target Organs Eyes, skin, mucous membrane, liver
See also: INTRODUCTION