Chromic acid hazards

Wescodyne West Chemical Products, New York, NY. Nonchromate cleaning methods are also available. Chromic acid is extremely hazardous and stringent precautions must be taken to avoid injury in its preparation and use (see Chapter 12). This procedure was designed for equipment which was custom-designed to significantly reduce the chromic acid hazard. 

Chromic acid concentrations m air (superseded by MDHS 52/3 (1998JJ Petroleum based adhesives m building operations Arsenic toxic hazards and precautions Spraying of highly flammable liquids... 

The technology is primarily applicable to the removal of inorganic fumes, vapors, and gases (e.g., chromic acid, hydrogen sulfide, ammonia, chlorides, fluorides, and SOj) volatile organic compounds (VOC) and particulate matter (PM), including PM less than or equal to 10 micrometers ( m) in aerodynamic diameter (PM,q), PM less than or equal to 2.5 m in aerodynamic diameter (PMj 5), and hazardous air pollutants (HAP) in particulate form (PM ap)-... 

Hazards arising from the oxidation of organic compounds are greater when the reactants are volatile, or present as a dust or an aerosol. Liquid oxygen and various concentrated acids, e.g. nitric, sulphuric or perchloric acid, and chromic acid are strong oxidizing agents. The use of perchloric acid or perchlorates has resulted in numerous explosions their use should be avoided when possible (refer to Table 6.5). 

Use of Less Hazardous Acid or Alkaline Compounds. The aluminum processing industry employs deoxider and desmutter systems in which chromic acid is used. This... 

Additional reductions in the amount of hazardous filter cake sludge produced were achieved with three process chemistry substitutions completed in September 1988, which eliminated a major source of chrome-containing wastes in the metal plating production facility. The initial substitutions replaced a chromic acid / nitric... 

Its toxicity and fire hazard are discussed by Sax (Ref 4). Davis (Ref la) described the use of chromic acid for prepn of TNB from TNT. Chromic acid is a parent compd of chromates and dichromates. 

Corona discharge is a popular method for applications on a large scale and because it can be carried out quickly in dry conditions in general it is less hazardous than chemical treatment and leaves no visible sign on the surfaces treated. On the other hand, there is some evidence that it is less effective in promoting adhesion to plastics than treatment with a substance like chromic acid. 

P.L. Manske, T.M. Stimpfel, and E.L. Gershey, A Less Hazardous Chromic Acid... 

All of the chromium reagents produce by-products and washings that contain hazardous chromium salts and must be collected as hazardous waste. In many cases, simple oxidants such as household bleach (sodium hypochlorite, NaOCl) can accomplish the same oxidations as chromic acid without using heavy metals, and without generating hazardous waste. Oxidations using sodium hypochlorite involve mildly acidic or basic conditions that may be better than chromic acid for acid-sensitive compounds. 

Chromic acid oxidation has been employed for the quantitation of p,p -DDE (35) and can be successfully applied to its confirmation on the residue scale (Table 1). Since this reaction is applicable to other DDT-related compounds and metabolites, the possible sources of interference hazards in a DDT-containing biological extract are many. 

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