Significance and Use
4.1 This guide includes chromates that are not readily soluble in water and that have water solubilities (Chromate ION) within the range of the more soluble calcium chromate and the much less soluble lead chromate. The major occupations involving potential exposure to insoluble chromates are in roasting of chromite ore, the manufacture of chromate pigments, the manufacture of coatings containing chromate pigments, and spray painting with these coatings. There is insufficient evidence to conclude that trivalent chromium compounds are carcinogenic.
Scope
1.1 This guide covers control procedures for the safe production, storage, transportation, and handling of only the hexavalent chromium compounds found in Table 1 and their various hydrates, and mixtures of coprecipitates of the same regardless of crystalline form.
| Chemical Name | Formula | Color Index NameA |
| Barium chromate | BaCrO4 | Pigment Yellow 31 |
| Barium potassium chromate | BaK3(CrO4)2 | Pigment Yellow 31 |
| Basic copper chromate | CuCrO4 | Not listed |
| Basic cadmium chromate | Cd2(OH)2CrO4 | Pigment Yellow 44 |
| Basic lead chromate | PbCrO4PbO | Pigment Orange 21 |
| Bismuth basic dichromate | Bi2O3CrO3 | Pigment Red 103 |
| Calcium chromate | CaCrO4 | None assigned |
| “Chromic chromate” | xCaO yCr2O 3 | Pigment Yellow 33 |
| Ferric chromate | Fe2(CrO4)3 | Pigment Yellow 45 |
| Basic ferric chromate | Fe(OH)CrO4 | Pigment Yellow 45 |
| Lead chromate | PbCrO4 | Pigment Yellow 34 |
| Lead molybdochromate | PbCrO4PbMoO4 | Pigment Red 104 |
| Potassium zinc chromate | K2O 4ano·4Cr4O3 | Pigment Yellow 36 |
| Strontium chromate | SrCrO4 | Pigment Yellow 32 |
| Zinc chromate | ZnCrO4 | Pigment Yellow 36 |
1.2 This guide is not intended to cover ( a) such “soluble” chromates as chromates of sodium, potassium, magnesium, or ammonium; (b) soluble bichromates; (c) chromic acid; (d) volatile chromyl compounds; (e) any trivalent chromium compound; or (f) elemental chromium. Omission of said compounds or classes of compounds should not be construed to mean that they may be handled without due regard to their particular physical, chemical, and toxicological hazards (9, 10, 11).
1.3 The chromate ion, CrO4−2 , depending upon the acidity, complexes to form di-, tri-, and higher polychromates; hence, the chromates listed in Table 1 may contain mixtures of polychromates, depending on the method of isolation and end use.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of whoever uses this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. (For more specific precautionary information see Section 5.)
