Hafnium

Synonyms & Trade Names
Celtium, Elemental hafnium, Hafnium metal
CAS No.
7440-58-6
RTECS No.
DOT ID & Guide
1326 170(powder, wet)
2545 135(powder, dry)
Formula
Hf
Conversion
IDLH
50 mg/m3 (as Hf)
See: 7440586
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).]
Measurement Methods
NIOSH S194 (II-5);
OSHA ID121
See: NMAM or OSHA Methods
Physical Description
Highly lustrous, ductile, grayish solid.
Molecular Weight
178.5
Boiling Point
8316°F
Melting Point
4041°F
Solubility
Insoluble
Vapor Pressure
0 mmHg (approx)
Ionization Potential
NA
Specific Gravity
13.31
Flash Point
NA
Upper Exposive Limit
NA
Lower Explosive Limit
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
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
Personal Protection/Sanitation
(See protection codes)
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 quarter-mask respirator.
Click here for information on selection of N, R, or P filters.

Up to 5 mg/m3:
(APF = 10) Any particulate respirator equipped with an N95, R95, or P95 filter (including N95, R95, and P95 filtering facepieces) except quarter-mask respirators. The following filters may also be used: N99, R99, P99, N100, R100, P100.
Click here for information on selection of N, R, or P filters.
(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 high-efficiency particulate filter.*

Up to 25 mg/m3:
(APF = 50) Any air-purifying, full-facepiece respirator with an N100, R100, or P100 filter.
Click here for information on selection of N, R, or P filters.
(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 an N100, R100, or P100 filter.
Click here for information on selection of N, R, or P filters.
Any appropriate escape-type, self-contained breathing apparatus

Important additional information about respirator selection

See also
INTRODUCTION   ICSC CARD: 0847
Page last reviewed: October 17, 2018