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Chromic acid and chromates

Synonyms & Trade Names
Chromic acid (CrO3): Chromic anhydride, Chromic oxide, Chromium(VI) oxide (1:3), Chromium trioxide
Synonyms of chromates (i.e., chromium(VI) compounds) such as zinc chromate vary depending upon the specific compound.
CAS No.
1333-82-0 (CrO3)
RTECS No.
GB6650000 (CrO3)
DOT ID & Guide
1755 154 (acid solution)
1463 141 (acid, solid)
Formula
CrO3 (acid)
Conversion
IDLH
Ca [15 mg/m3 {as Cr(VI)}]
See: 1333820
Exposure Limits
NIOSH REL
(as Cr): Ca TWA 0.001 mg/m3 See Appendix A See Appendix C
OSHA PEL
(as CrO3): TWA 0.005 mg/m3 See Appendix C
Measurement Methods

NIOSH 7600 , 7604 , 7605 , 7703 , 9101;
OSHA ID103 , ID215 , W4001
See: NMAM or OSHA Methods
Physical Description
CrO3: Dark-red, odorless flakes or powder. [Note: Often used in an aqueous solution (H2CrO4).]
MW:
100.0
BP:
482°F (Decomposes)		 MLT: 387°F (Decomposes)
Sol:
63%
VP:
Very low
IP:
NA
Sp.Gr:
2.70 (CrO3)
Fl.P:
NA
UEL:
NA
LEL:
NA
CrO3: Noncombustible Solid, but will accelerate the burning of combustible materials.
Incompatibilities & Reactivities
Combustible, organic, or other readily oxidizable materials (paper, wood, sulfur, aluminum, plastics, etc.); corrosive to metals
Exposure Routes
inhalation, ingestion, skin and/or eye contact
Symptoms
irritation respiratory system; nasal septum perforation; liver, kidney damage; leukocytosis (increased blood leukocytes), leukopenia (reduced blood leukocytes), eosinophilia; eye injury, conjunctivitis; skin ulcer, sensitization dermatitis; [potential occupational carcinogen]
Target Organs
Blood, respiratory system, liver, kidneys, eyes, skin
Cancer Site
[lung cancer]
Personal Protection/Sanitation
(See protection codes)
Skin: Prevent skin contact
Eyes: Prevent eye contact
Wash skin: When contaminated
Remove: When wet or contaminated
Change: Daily
Provide: Eyewash, Quick drench
First Aid
(See procedures)
Eye: Irrigate immediately
Skin: Soap flush immediately
Breathing: Respiratory support
Swallow: Medical attention immediately
Respirator Recommendations

NIOSH

At concentrations above the NIOSH REL, or where there is no REL, at any detectable concentration:
(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   See ICSC CARD: 1194   See MEDICAL TESTS: 0051
 

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