Hafnium

This chemical does not meet GHS hazard criteria for 34.4% (124 of 360) of reports.

H250 (50.6%): Catches fire spontaneously if exposed to air [Danger Pyrophoric liquids]

P210, P222, P231, P233, P280, P302+P335+P334, and P370+P378 (click each P-code to see the statement)

Aggregated GHS information provided per 360 reports by companies from 10 notifications to the ECHA C&L Inventory.

Reported as not meeting GHS hazard criteria per 124 of 360 reports by companies.

There are 9 notifications provided by 236 of 360 reports by companies with hazard statement code(s).

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

Not Classified

Fresh air, rest.

Rinse contaminated clothes (fire hazard) with plenty of water. Remove contaminated clothes. Rinse and then wash skin with water and soap.

Rinse with plenty of water (remove contact lenses if easily possible).

Rinse mouth.

Excerpt from NIOSH Pocket Guide for Hafnium:

Eye: IRRIGATE IMMEDIATELY - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately.

Skin: SOAP WASH PROMPTLY - If this chemical contacts the skin, promptly wash the contaminated skin with soap and water. If this chemical penetrates the clothing, promptly remove the clothing and wash the skin with soap and water. Get medical attention promptly.

Breathing: RESPIRATORY SUPPORT - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. If breathing has stopped, perform artificial respiration. Keep the affected person warm and at rest. Get medical attention as soon as possible.

Swallow: MEDICAL ATTENTION IMMEDIATELY - If this chemical has been swallowed, get medical attention immediately. (NIOSH, 2024)

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]:

Refer to the "General First Aid" section. (ERG, 2024)

General First Aid:

· Call 911 or emergency medical service.

· Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination.

· Move victim to fresh air if it can be done safely.

· Administer oxygen if breathing is difficult.

· If victim is not breathing:

-- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance.

-- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).

-- If no pulse detected or no respiratory medical device available, provide continuous compressions. Conduct a pulse check every two minutes or monitor for any signs of spontaneous respirations.

· Remove and isolate contaminated clothing and shoes.

· For minor skin contact, avoid spreading material on unaffected skin.

· In case of contact with substance, remove immediately by flushing skin or eyes with running water for at least 20 minutes.

· For severe burns, immediate medical attention is required.

· Effects of exposure (inhalation, ingestion, or skin contact) to substance may be delayed.

· Keep victim calm and warm.

· Keep victim under observation.

· For further assistance, contact your local Poison Control Center.

· Note: Basic Life Support (BLS) and Advanced Life Support (ALS) should be done by trained professionals.

In Canada, an Emergency Response Assistance Plan (ERAP) may be required for this product. Please consult the shipping paper and/or the "ERAP" section.

(General first aid procedures)

Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately.

Skin: Soap wash promptly - If this chemical contacts the skin, promptly wash the contaminated skin with soap and water. If this chemical penetrates the clothing, promptly remove the clothing and wash the skin with soap and water. Get medical attention promptly.

Breathing: Respiratory support

Swallow: Medical attention immediately - If this chemical has been swallowed, get medical attention immediately.

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:

DO NOT USE WATER, CO2 OR FOAM ON MATERIAL ITSELF. Some of these materials may react violently with water. CAUTION: For Xanthates, UN3342 and for Dithionite (Hydrosulfite/Hydrosulphite) UN1384, UN1923 and UN1929, USE FLOODING AMOUNTS OF WATER for SMALL AND LARGE fires to stop the reaction. Smothering will not work for these materials, they do not need air to burn.

SMALL FIRE: Dry chemical, soda ash, lime or DRY sand, EXCEPT for UN1384, UN1923, UN1929 and UN3342.

LARGE FIRE: DRY sand, dry chemical, soda ash or lime EXCEPT for UN1384, UN1923, UN1929 and UN3342, or withdraw from area and let fire burn. CAUTION: UN3342 when flooded with water will continue to evolve flammable Carbon disulfide/Carbon disulphide vapors. If it can be done safely, move undamaged containers away from the area around the fire.

FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Do not get water inside containers or in contact with substance. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. (ERG, 2024)

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]:

DO NOT USE WATER, FOAM OR CO2. Dousing metallic fires with water will generate hydrogen gas, an extremely dangerous explosion hazard, particularly if fire is in a confined environment (i.e., building, cargo hold, etc.). Use DRY sand, graphite powder, dry sodium chloride-based extinguishers, or class D extinguishers. Confining and smothering metal fires is preferable rather than applying water. If it can be done safely, move undamaged containers away from the area around the fire.

FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: If impossible to extinguish, protect surroundings and allow fire to burn itself out. (ERG, 2024)

Use special powder, dry sand, water in large amounts.

If material on fire or involved in fire: Use suitable dry powder. ... Use dry chemical or carbon dioxide. ... Use water only if flooding quantities are available. /Hafnium powder, dry/

If material on fire or involved in fire: Use suitable dry powder. ... Use dry chemical or carbon dioxide. ... Use water only if flooding quantities are available. /Hafnium powder, wetted/

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· Stay upwind, uphill and/or upstream.

· Keep unauthorized personnel away.

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.

· Do not touch or walk through spilled material.

· Stop leak if you can do it without risk.

Small Spill

CAUTION: For spills of Xanthates, UN3342 and for Dithionite (Hydrosulfite/Hydrosulphite), UN1384, UN1923 and UN1929, dissolve in 5 parts water and collect for proper disposal.

CAUTION: UN3342 when flooded with water will continue to evolve flammable Carbon disulfide/Carbon disulphide vapors.

· Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain.

· Use clean, non-sparking tools to collect material and place it into loosely covered plastic containers for later disposal.

· Prevent entry into waterways, sewers, basements or confined areas.

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: Increase the immediate precautionary measure distance, in the downwind direction, as necessary.

FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]:

LARGE SPILL: Consider initial downwind evacuation for at least 50 meters (160 feet).

Immediate precautionary measure

· Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

· For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.

· For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind direction, as necessary.

· If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions.

Large Spill

· Consider initial downwind evacuation for at least 50 meters (160 feet).

Remove all ignition sources. Evacuate danger area! Consult an expert! Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Wet powder to prevent dusting and ignition. Sweep spilled substance into covered water-filled containers. Then store and dispose of according to local regulations. Do NOT wash away into sewer. Do NOT absorb in saw-dust or other combustible absorbents.

Persons not wearing protective equipment and clothing should be restricted from areas of spills until cleanup has been completed. 1. Ventilate area of spill. 2. Collect spilled material in most convenient and safe manner and deposit in sealed containers for reclamation, or for disposal in secured sanitary landfill. Liq containing hafnium...should be absorbed in vermiculite, dry sand, earth, or similar material.

Any spilled powder should be cleaned up immediately with water so that it has no chance to dry in place.

Spillage disposal: Evacuate danger area. Eliminate all sources of ignition. Do not wash away into sewer because it is flammable. Do not absorb in sawdust or other combustible absorbents. Wet the powder to prevent formation of dust or ignition; carefully collect the powder into sealable containers, and remove it to a safe place. During this procedure, use extra personal protection, e.g., a P2 filter respirator for harmful particles.

Environmental considerations: land spill: Dig a pit, pond, lagoon, holding area to contain liquid or solid material. ... Apply appropriate foam to diminish vapor and fire hazard. ... /SRP: If time permits, pits, ponds, lagoons, soak holes, or holding areas should be sealed with an impermeable flexible membrane liner./ /Hafnium powder, wetted/

Environmental considerations: water spill: Use natural barriers or oil spill control booms to limit spill travel. /Hafnium powder, wetted/

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

If the quantity justifies recovery, get in touch with the supplier for special instructions.

Used papers and cloths which have become contaminated with powders should be kept wet in covered Containers until they are /disposed/.

Ventilation control: ...all processes using these materials /zirconium and hafnium/ should be...ventilated to keep air-borne contaminants far below.../5 mg/cu m/.

Care should be taken when machining metal or when handling hot sponge hafnium.

All sources of ignition, including static electric charges, should be eliminated from areas in which powder is to be handled. All surfaces...should be impervious and seamless so that they can be washed down with water and kept completely free from dust. Dried powders should be disturbed and handled as little as possible and then only with non-sparking tools.

The worker should immediately wash the skin when it becomes contaminated.

For more Preventive Measures (Complete) data for HAFNIUM, ELEMENTAL (16 total), please visit the HSDB record page.

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. Do not touch or walk through spilled material. Stop leak if you can do it without risk.

SMALL SPILL: CAUTION: For spills of Xanthates, UN3342 and for Dithionite (Hydrosulfite/Hydrosulphite), UN1384, UN1923 and UN1929, dissolve in 5 parts water and collect for proper disposal. CAUTION: UN3342 when flooded with water will continue to evolve flammable Carbon disulfide/Carbon disulphide vapors. Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain. Use clean, non-sparking tools to collect material and place it into loosely covered plastic containers for later disposal. Prevent entry into waterways, sewers, basements or confined areas. (ERG, 2024)

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. Do not touch or walk through spilled material. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. (ERG, 2024)

Fireproof. Separated from strong oxidants, strong acids and halogens. Keep under inert gas. Store only in original container.

Storage: Store hafnium in a fireproof area. Keep it separate from strong oxidizing agents, strong bases, halogens, phosphorus, and sulfur. Keep stored under water.

· Wear positive pressure self-contained breathing apparatus (SCBA).

· Wear chemical protective clothing that is specifically recommended by the manufacturer when there is NO RISK OF FIRE.

· Structural firefighters' protective clothing provides thermal protection but only limited chemical protection.

0.50 [mg/m3]

5.5 [mg/m3]

33 [mg/m3]

0.5 mg/m³

TWA 0.5 mg/m3 [*Note: The REL also applies to other hafnium compounds (as Hf).]

0.5 [mg/m3], as Hf

TWA 0.5 mg/m3 [*Note: The PEL also applies to other hafnium compounds (as Hf).]

50 mg Hf/m3 (NIOSH, 2024)

50.0 [mg/m3], as Hf

Excerpts from Documentation for IDLHs: No inhalation toxicity data are available on which to base an IDLH for hafnium compounds. Therefore, the revised IDLH for hafnium compounds is 50 mg Hf/m3 based on acute oral toxicity data in animals . . .

Recommended Exposure Limit: 50 mg/cu m (as Hf)

50 mg/m³

50 mg/m3 (as Hf)

See: 7440586

8 hr Time Weighted Avg (TWA): 0.5 mg/cu m. /Hafnium and compounds, as Hf/

Excursion Limit Recommendation: Excursions in worker exposure levels may exceed 3 times the TLV-TWA for no more than a total of 30 minutes during a work day, and under no circumstances should they exceed 5 times the TLV-TWA, provided that the TLV-TWA is not exceeded. /Hafnium and compounds, as Hf/

0.5 mg/m

0.5 mg/m³ [1990]

· DO NOT USE WATER, CO2 OR FOAM ON MATERIAL ITSELF.

· Some of these materials may react violently with water.

CAUTION: For Xanthates, UN3342 and for Dithionite (Hydrosulfite/Hydrosulphite) UN1384, UN1923 and UN1929, USE FLOODING AMOUNTS OF WATER for SMALL AND LARGE fires to stop the reaction. Smothering will not work for these materials, they do not need air to burn.

Small Fire

· Dry chemical, soda ash, lime or DRY sand, EXCEPT for UN1384, UN1923, UN1929 and UN3342.

Large Fire

· DRY sand, dry chemical, soda ash or lime EXCEPT for UN1384, UN1923, UN1929 and UN3342, or withdraw from area and let fire burn.

CAUTION: UN3342 when flooded with water will continue to evolve flammable Carbon disulfide/Carbon disulphide vapors.

· If it can be done safely, move undamaged containers away from the area around the fire.

Fire Involving Tanks, Rail Tank Cars or Highway Tanks

· Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles.

· Do not get water inside containers or in contact with substance.

· Cool containers with flooding quantities of water until well after fire is out.

· Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank.

· ALWAYS stay away from tanks in direct contact with flames.

· DO NOT USE WATER, FOAM OR CO2.

· Dousing metallic fires with water will generate hydrogen gas, an extremely dangerous explosion hazard, particularly if fire is in a confined environment (i.e., building, cargo hold, etc.).

· Use DRY sand, graphite powder, dry sodium chloride-based extinguishers, or class D extinguishers.

· Confining and smothering metal fires is preferable rather than applying water.

Hafnium powder, dry, is a grayish metallic colored powder. Dust from dry powder may be ignited by static electricity. The dry powder reacts with moisture to produce hydrogen, a flammable gas. The heat from this reaction may be sufficient to ignite the hydrogen. It does not appreciably react with large quantities of water.

Grayish powdery solid wetted with water.

Other Solid

Highly lustrous, ductile, grayish solid; [NIOSH]

GREY POWDER.

Highly lustrous, ductile, grayish solid.

Gray crystals

Highly lustrous metal of hexagonal crystal structure

Hard, shiny, ductile metal with a color very similar to that of stainless steel ... hafnium sponge metal is a dull powder gray

Crystallizes in a...cubic system which transforms to a hexagonal close-packed system below 2033 K.

8316 °F at 760 mmHg (NIOSH, 2024)

4603 °C @760 [mm Hg]

4041 °F (NIOSH, 2024)

Insoluble (NIOSH, 2024)

Hafnium is slowly attacked by concentrated sulfuric acid. Hafnium is unaffected by nitric acid in all concentrations. It is resistant to dilute solutions of hydrochloric acid and sulfuric acid. Hafnium is attacked by all mineral acids if traces of fluorides are present. Hafnium is very resistant to attack by alkalies.

Soluble in hydrogen fluoride

Solubility in water: none

Insoluble

13.31 (NIOSH, 2024) - Denser than water; will sink

Zirconium and hafnium chemistries are almost identical ... the density of zirconium is about half that of hafnium.

Relative density (water = 1): 13.31

13.3 @25 °C

0 mmHg (approx) (NIOSH, 2024)

1X10-05 Pa at 1767 °C; 1X10-04 Pa at 2007 °C

0 mmHg (approx)

20 °C for dust cloud

May explosively decompose on shock, friction, or concussion. /Hafnium powder/

Good corrosion resistance

Atomic number: 72; ductile; has been successfully alloyed with iron, titanium, niobium, tantalum, and other metals; rapidly absorbs hydrogen to form HfH at 700 °C; halogens react directly to form tetrahalides; properties are considerably influenced by impurities of zirconium present

Standard molar enthalpy of formation (kJ/mol at 298.15 K): 0 (crystal), 619.2 (gas); standard molar Gibbs energy of formation (kJ/mol at 298.15 K): 576.5 (gas); standard molar entropy (J/mol-K at 298.15 K): 43.6 (crystal), 186.9 (gas); molar heat capacity at constant pressure (mol/K at 298.15 K): 25.7 (crystal), 20.8 (gas)

High thermal neutron cross-section (115 barns); high strength

Six naturally occurring isotopes: 180 (35.22%); 178 (27.1%); 177 (18.56%); 179 (13.75%); 176 (5.21%); 174 (0.163%; alpha-emitter...); artificial isotopes: 157; 158; 168-173; 175; 181-183.

For more Other Experimental Properties (Complete) data for HAFNIUM, ELEMENTAL (8 total), please visit the HSDB record page.

electron density of states

dielectric constant

electromagnetic induction

optical coefficient

crystal structure

fusion temperature

Debye frequency

Highly flammable. The dry powder reacts with moisture to produce hydrogen, a flammable gas. The heat from this reaction may be sufficient to ignite the hydrogen. It does not appreciably react with large quantities of water.

Highly flammable. The dry powder is pyrophoric and readily ignitable by friction, heat or static electricity and burns fiercely. 5-10% water by mass slightly reduces the ease of ignition, but combustion of the damp powder proceeds explosively. A minimum of 25% water is necessary. Insoluble in water.

Metals, Elemental and Powder, Active

Water and Aqueous Solutions

Strong Reducing Agent

Pyrophoric

Highly Flammable

Metals, such as HAFNIUM POWDER (reactivity similar to zirconium), are reducing agents and tend to react with oxidizing agents. Their reactivity is strongly influenced by their state of subdivision: in bulk they often resist chemical combination; in powdered form they may react very rapidly. Thus, as a bulk metal it is somewhat unreactive, but finely divided material may be pyrophoric. The metal reacts exothermically with compounds having active hydrogen atoms (such as acids and water) to form flammable hydrogen gas and caustic products. The reactions are less vigorous than the similar reactions of alkali metals, but the released heat can still ignite the released hydrogen. Materials in this group may react with azo/diazo compounds to form explosive products. These metals and the products of their corrosion by air and water can catalyze polymerization reactions in several classes of organic compounds; these polymerizations sometimes proceed rapidly or even explosively. Some metals in this group form explosive products with halogenated hydrocarbons.

Liable to spontaneous ignition. HAFNIUM POWDER is a reducing agent. Forms explosive mixtures with most oxidizing materials Reacts exothermically with compounds having active hydrogen atoms (such as acids and water) to form flammable hydrogen gas and caustic products. The reactions are less vigorous than the similar reactions of alkali metals, but the released heat can still ignite the released hydrogen. Materials in this group may react with azo/diazo compounds to form explosive products. These metals and the products of their corrosion by air and water can catalyze polymerization reactions in several classes of organic compounds; these polymerizations sometimes proceed rapidly or even explosively. Some metals in this group form explosive products with halogenated hydrocarbons. Can react explosively with oxidizing materials.

Although /hafnium/ is relatively inert, when powdered it becomes very reactive. The dry powder may react explosively at elevated temperatures with nitrogen, phosphorus, oxygen, sulfur and other non-metals. The halogens react similarly, and in contact with hot concentrated nitric acid and other oxidants it may explode (often after a delay with nitric acid). The powder is pyrophoric and readily ignitable by friction, heat or static sparks, and if dry burns fiercely. Presence of water (5-10%) slightly reduces the ease of ignition, but combustion of the damp powder proceeds explosively (the oxygen content of water, 89%, being much higher than that of air).

Strong oxidizers, chlorine.

Reacts violently with strong acids, strong oxidants, halogens causing explosion hazard. /Hafnium powder/

Strong oxidizers, chlorine

inhalation, ingestion, skin and/or eye contact

Redness.

In Animals: irritation eyes, skin, mucous membrane; liver damage

Eyes, skin, mucous membrane, liver

Occupational hepatotoxin - Secondary hepatotoxins: the potential for toxic effect in the occupational setting is based on cases of poisoning by human ingestion or animal experimentation.

Routine medical examinations should be provided to each employee who is exposed to hafnium and compounds at potentially hazardous levels. The employer should screen employees for history of liver disease. ... The importance of this organ in the biotransformation and detoxification of foreign substances should be considered before exposing persons with impaired liver function. Only those giving a positive history of these conditions should be referred for further medical examinations.

/SIGNS AND SYMPTOMS/ Lungs may be affected by repeated or prolonged exposure. The substance may have effects on the liver.

/SIGNS AND SYMPTOMS/ Overexposure to hafnium and its compounds may cause mild irritation of the eyes, skin, and mucous membranes.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ To evaluate the biocompatibility of refractory metals, titanium, hafnium, niobium, tantalum and rhenium were implanted in rats, and histological observation and elemental mapping were performed by X-ray scanning analytical microscope (XSAM) and electron probe microanalyzer (EPMA). The titanium, hafnium, niobium, tantalum and rhenium wires were implanted in the subcutaneous tissue of the abdominal region and in femoral bone marrow of rats for either 2 or 4 weeks. No inflammatory response was observed around the implants, and all the implants were encapsulated with thin fibrous connective tissue. No dissolution of these metals was detected by XSAM in the soft tissue. Histological examination of the hard tissue showed that the amount of new bone formation decreased slightly from the second to the fourth week after implantation, and that the percentage of bone in contact with the implant increased markedly over the same period. No dissolution of these metals was detected by EPMA in the hard tissue. The Ca and P intensities in the mapping images of newly formed bone were higher after 4 weeks than those after 2 weeks, which suggests that the newly formed bone continued to mature from 2 to 4 weeks after implantation. These results indicate that titanium, hafnium, niobium, tantalum and rhenium have good biocompatibility and osteoconductivity.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ The aim of the present experimental study was to evaluate the tissue response to hafnium (Hf) a reactive metal closely related to titanium (Ti) and zirconium (Zr). Hf has not been previously evaluated as implant material in a biologic environment. In a first experiment, 21 machined Hf non-threaded implants (test) and 21 similar Ti implants (control) were inserted in the abdominal wall of 21 rats. Animals were sacrificed after 8 days (6 rats), 6 (7 rats) and 12 weeks (8 rats). In a second experiment, 18 rabbits received 18 Hf and 18 Ti threaded implants in their tibiae, one implant in each tibia. The rabbits were sacrificed after 6, 12 and 24 weeks (6 animals/time interval). The bulk metal of the abdominal wall implants, embedded together with the surrounding tissue, was electrolytically dissolved and semithin (1 microm) sections of the intact tissue-implant interface were evaluated by light microscopy (morphometry). Bone-implant contact and bone area within threads were evaluated in ground sections. In soft tissues, a fluid space containing predominantly monocytes/macrophages surrounded the abdominal implants at 8 days. At 6 and 12 weeks, a fibrous capsule, consisting of layers of macrophages and fibroblasts, surrounded the implants. Macrophages, including multinuclear giant cells, always formed the innermost layer in contact with the implant surface. No quantitative or qualitative difference in the tissue organization was detected between Ti and Hf implants. In rabbits, 6 weeks after insertion, the proximal two threads located within the cortical bone were filled with bone in contact with Hf and Ti. The distal threads contained bone marrow. After 12 and 24 weeks, mature bone was present in the proximal 3-4 implant threads. No statistically significant difference was found between Hf and Ti implants at any time periods. It is concluded that Hf is an interesting metal for biomedical applications in bone and soft tissue.

/OTHER TOXICITY INFORMATION/ There have been no published studies on the toxicity of metallic hafnium.

Environmental effects from the substance have not been investigated adequately.

Hafnium is...never found free in nature. It is always found associated with the more plentiful zirconium.

Environmental effects from the substance have not been investigated adequately.

Hafnium is...never found free in nature. It is always found associated with the more plentiful zirconium.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

If the quantity justifies recovery, get in touch with the supplier for special instructions.

Used papers and cloths which have become contaminated with powders should be kept wet in covered Containers until they are /disposed/.

/GUIDE 135: SUBSTANCES - SPONTANEOUSLY COMBUSTIBLE/ Fire or Explosion: Flammable/combustible material. May ignite on contact with moist air or moisture. May burn rapidly with flare-burning effect. Some react vigorously or explosively on contact with water. Some may decompose explosively when heated or involved in a fire. May re-ignite after fire is extinguished. Runoff may create fire or explosion hazard. Containers may explode when heated. /Hafnium powder, dry/

/GUIDE 135: SUBSTANCES - SPONTANEOUSLY COMBUSTIBLE/ Health: Fire will produce irritating, corrosive and/or toxic gases. Inhalation of decomposition products may cause severe injury or death. Contact with substance may cause severe burns to skin and eyes. Runoff from fire control may cause pollution. /Hafnium powder, dry/

/GUIDE 135: SUBSTANCES - SPONTANEOUSLY COMBUSTIBLE/ Public Safety: CALL Emergency Response Telephone Number ... . As an immediate precautionary measure, isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids. Stay upwind. Keep unauthorized personnel away. Keep out of low areas. /Hafnium powder, dry/

/GUIDE 135: SUBSTANCES - SPONTANEOUSLY COMBUSTIBLE/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing that is specifically recommended by the manufacturer. It may provide little or no thermal protection. Structural firefighters' protective clothing will only provide limited protection. /Hafnium powder, dry/

For more DOT Emergency Guidelines (Complete) data for HAFNIUM, ELEMENTAL (16 total), please visit the HSDB record page.

1326 170(powder, wet)

2545 135(powder, dry)

UN 4237; Hafnium powder, dry

UN 2545; Hafnium powder, dry

UN 1326; Hafnium powder, wetted with not less than 25% water

IMO 4.2; Hafnium powder, dry

IMO 4.1; Hafnium powder, wetted with not less than 25% water

49 167 12; Hafnium metal, wet

49 167 11; Hafnium metal, dry

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./

The International Air Transport Association (IATA) Dangerous Goods Regulations are published by the IATA Dangerous Goods Board pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry carrier regulations to be followed by all IATA Member airlines when transporting hazardous materials.

The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article.

Spontaneously Combustible

Flammable Solid

UN Hazard Class: 4.2; UN Pack Group: I