Hafnium

Synonyms & Trade Names

Celtium, Elemental hafnium, Hafnium metal

CAS No.

7440-58-6

RTECS No.

MG4600000

DOT ID & Guide

1326 170(powder, wet)
2545 135(powder, dry)

Formula

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

Specific Gravity

13.31

Flash Point

Upper Explosive Limit

Lower Explosive Limit

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

Hafnium

NIOSH REL

OSHA PEL

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