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SECTION 1. CHEMICAL IDENTIFICATION

CHEMINFO Record Number: 547
CCOHS Chemical Name: Chromium

Synonyms:
Chrome
Elemental chromium
Chromium metal

Chemical Name French: Chrome
Chemical Name Spanish: Cromo (polvo)
CAS Registry Number: 7440-47-3
RTECS Number(s): GB4200000
EU EINECS/ELINCS Number: 231-157-5
Chemical Family: Chromium and compounds / elemental chromium / chromium metal
Molecular Formula: Cr
Structural Formula: Cr

SECTION 2. DESCRIPTION

Appearance and Odour:
Steel-grey, lustrous metal; odourless (3); available as lumps, granules, powder or high purity single crystals.(2)

Odour Threshold:
Not applicable

Warning Properties:
Not applicable

Composition/Purity:
Chromium occurs as chromium metal (elemental chromium) and as chromium compounds (for example, chromous, chromic and chromate compounds). This record contains information only on chromium metal. There are CHEMINFO records on a number of chromium compounds. NOTE: Many publications describe various toxic effects and properties of "chromium". In most cases the information applies to chromium compounds in general, and not to chromium metal.

Uses and Occurrences:
Component of stainless steels and high temperature alloys; coating on metal and plastic (electroplated from solutions of chromium salts); synthesis of inorganic pigments (2); manufactured metal goods.


SECTION 3. HAZARDS IDENTIFICATION

POTENTIAL HEALTH EFFECTS

Effects of Short-Term (Acute) Exposure

Inhalation:
Chromium metal dust appears to have low toxicity by all routes of occupational exposure. There is very little published information on the toxic effects of chromium metal, but the metal is practically insoluble and unreactive in the body.
However, exposure to metal dust usually occurs during operations such as cutting, grinding and welding, which often involve exposure to hazardous dusts and fumes of chromium compounds and other materials.

Chromium dust can probably cause coughing and mild temporary irritation (non-specific dust effects).

Skin Contact:
Dust is not irritating to the skin, but use of rigorous washing procedures to remove dust may cause skin irritation.

Eye Contact:
Chromium metal dust is not irritating to the eyes except as a "foreign object".(6) Some tearing, blinking and mild temporary pain may occur as particles are rinsed from the surface of the eye.

Ingestion:
Metallic chromium probably is practically non-toxic by ingestion and is not absorbed into the body. It probably can be slowly oxidized to trivalent chromium compounds by stomach acids, but trivalent chromium has low toxicity and is poorly absorbed. Almost all of the chromium probably is eliminated in feces.

Effects of Long-Term (Chronic) Exposure

SKIN: Metallic chromium probably does not cause irritation or sensitization. Some chromium compounds (primarily hexavalent chromium) can cause sensitization (chrome allergy).(8)
INHALATION: Pulmonary disease was reported in workers exposed to dust containing chromium metal and ferrichrome alloys, but also containing other dusts and fumes. Exposure to chromium metal dust does not give rise to lung disease (pulmonary fibrosis or pneumoconiosis).(9) Chromium metal has not been reported as a respiratory sensitizer.

Carcinogenicity:

No adequate human or animal information is available.(1,12)

The International Agency for Research on Cancer (IARC) has concluded that this chemical is not classifiable as to its carcinogenicity to humans (Group 3).

The American Conference of Governmental Industrial Hygienists (ACGIH) has designated this chemical as not classifiable as a human carcinogen (A4).

The US National Toxicology Program (NTP) has not listed this chemical in its report on carcinogens.

Teratogenicity and Embryotoxicity:
No human or animal information available. No embryotoxic or teratogenic effects are likely.

Reproductive Toxicity:
No information available

Mutagenicity:
No information available

Toxicologically Synergistic Materials:
No information available

Potential for Accumulation:
Chromium dust can accumulate in the lungs.

Health Comments:
Interpretation of the available information is complicated by mixed exposures. Therefore, it is difficult to state conclusively that chromium metal has no significant toxic effects.


SECTION 4. FIRST AID MEASURES

Inhalation:
If symptoms are experienced, remove source of contamination or move victim to fresh air. Obtain medical advice immediately.

Skin Contact:
If irritation occurs, wash gently and thoroughly with water and non-abrasive soap. If irritation persists, obtain medical advice immediately.

Eye Contact:
If irritation occurs, immediately flush the contaminated eye(s) with lukewarm, gently flowing water for 10 minutes, by the clock, holding the eyelid(s) open. If irritation persists, repeat flushing. Obtain medical advice immediately.

Ingestion:
Have victim rinse mouth thoroughly with water. DO NOT INDUCE VOMITING. Have victim drink 240 to 300 mL (8 to 10 oz.) of water. If vomiting occurs naturally, rinse mouth and repeat administration of water. Obtain medical advice immediately.

First Aid Comments:
All first aid procedures should be periodically reviewed by a physician familiar with the material and its conditions of use in the workplace.



SECTION 5. FIRE FIGHTING MEASURES

Flash Point:
Not applicable (does not form vapour)

Lower Flammable (Explosive) Limit (LFL/LEL):
0.23 g/L (dust cloud) (13)

Upper Flammable (Explosive) Limit (UFL/UEL):
Not available

Autoignition (Ignition) Temperature:
Not applicable

Sensitivity to Mechanical Impact:
Not sensitive; stable material.

Sensitivity to Static Charge:
Powdered chromium metal is probably not sensitive to static discharge.

Combustion and Thermal Decomposition Products:
Oxides of chromium

Fire Hazard Summary:
When heated in a flame, chromium dust may be ignitable.(5) Minimum ignition temperature, cloud: 580 deg C; layer: 400 deg C.(13)

Extinguishing Media:
Use extinguishing agents appropriate for surrounding fire. Do not use carbon dioxide, which may form an explosive mixture with powdered chromium.(11)

Fire Fighting Instructions:
Chromium dust will not burn unless heated in a flame.(5)



NATIONAL FIRE PROTECTION ASSOCIATION (NFPA) HAZARD IDENTIFICATION

NFPA - Comments:
NFPA has no listing for this chemical in Codes 49 or 325.


SECTION 9. PHYSICAL AND CHEMICAL PROPERTIES

Molecular Weight: 52.00

Conversion Factor:
Not applicable

Physical State: Solid
Melting Point: 1900 deg C (3452 deg F)
Boiling Point: 2642 deg C (4788 deg F)
Relative Density (Specific Gravity): 7.2 (water = 1)
Solubility in Water: Not soluble
Solubility in Other Liquids: Not soluble in organic solvents or bases. Soluble in halogens and halogen acids (e.g. hydrochloric acid) and dilute sulphuric acid (reacts).
Coefficient of Oil/Water Distribution (Partition Coefficient): Not applicable
pH Value: Not applicable
Vapour Density: Not applicable
Vapour Pressure: Practically zero at room temperature
Saturation Vapour Concentration: Not applicable
Evaporation Rate: Not applicable
Critical Temperature: Not applicable

SECTION 10. STABILITY AND REACTIVITY

Stability:
Stable material

Hazardous Polymerization:
Does not occur

Incompatibility - Materials to Avoid:

NOTE: Chemical reactions that could result in a hazardous situation (e.g. generation of flammable or toxic chemicals, fire or detonation) are listed here. Many of these reactions can be done safely if specific control measures (e.g. cooling of the reaction) are in place. Although not intended to be complete, an overview of important reactions involving common chemicals is provided to assist in the development of safe work practices.


OXIDIZING AGENTS - powdered chromium becomes incandescent.(10)

CARBON DIOXIDE - a heated mixture of chromium powder and carbon dioxide may be ignitable and explosive. Bulk metal may burn in the presence of carbon dioxide.(11)

Hazardous Decomposition Products:
None

Corrosivity to Metals:
Not corrosive


SECTION 11. TOXICOLOGICAL INFORMATION

EYE IRRITATION (rabbit): Chromium metal implanted into rabbits' eyes was tolerated well while under observation for one year.(6)

CARCINOGENICITY: In a series of studies, rats were injected with powdered chromium. The number of tumours was not significantly greater in the test animals than in controls. Similar results were observed in experiments with mice. When tested on rabbits, one of three animals developed a tumour.(1)
IARC evaluation of the carcinogenicity of chromium metal to experimental animals: inadequate evidence.(12)


SECTION 16. OTHER INFORMATION

Selected Bibliography:
(1) IARC Monographs on the evaluation of the carcinogenic risk of chemicals to humans. Vol. 23. IARC, 1980. p. 205-323
(2) Hawley's condensed chemical dictionary. 11th ed. Van Nostrand Reinhold, 1987. p. 280
(3) The Merck index: an encyclopedia of chemicals, drugs, and biologicals. 10th ed. Merck. 1983. p. 317
(4) HSDB record for chromium. Complete update on 03/08/88; printed 1989 01 20
(5) Browning, E. Toxicity of industrial metals. 2nd ed. Butterworths, 1969. p. 119-131
(6) Grant, W.M. Toxicology of the eye. 3rd ed. Charles C. Thomas, 1986. p. 234
(7) Grant, W.M. Toxicology of the eye. Vol. 1. 2nd ed. Charles C. Thomas, 1974. p. 290
(8) Handbook on the toxicology of metals. Elsevier/North-Holland Biomedical Press, 1979. p. 383-397
(9) Documentation of the threshold limit values and biological exposure indices. 5th ed. ACGIH, 1986. p. 139-140
(10) Fire protection guide on hazardous materials. 9th ed. National Fire Protection Association, 1986. NFPA 491
(11) Bretherick, L. Handbook of reactive chemical hazards. 3rd ed. Butterworths, 1985. p. 192
(12) IARC monographs on the evaluation of carcinogenic risks to humans. Supplement 7. IARC, 1987
(13) Fire protection handbook. 16th ed. National Fire Protection Association, 1986. p. 5-99 - 5-100
(14) NIOSH pocket guide to chemical hazards. NIOSH, June 1994. p. 72-73

Information on chemicals reviewed in the CHEMINFO database is drawn from a number of publicly available sources. A list of general references used to compile CHEMINFO records is available in the database Help.


Review/Preparation Date: 1989-10-25

Revision Indicators:
PEL-TWA 1993-03-01
WHMIS (disclosure list) 1993-03-01
Trans PEL-TWA 1993-04-01
TDG 1994-02-01
TLV-TWA 1994-11-01
TLV comments 1995-11-01
Bibliography 1995-11-01
EEC classification 1996-05-01
US transport 1996-05-01
Sampling 1996-05-01
EEC number 1996-05-01
TLV comments 1998-08-01
Respiratory guidelines 1995-11-01
PEL-TWA transitional 2003-10-28
PEL transitional comments 2003-10-28



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