EPA Issues Stricter Hex Chrome Rules

Graph of CrVI Emissions from EPA National Emissions Inventory 2005

Graph of CrVI Emissions from EPA National Emissions Inventory 2005

National Emission Standards for Hazardous Air Pollutant Emissions: Hard and Decorative Chromium Electroplating and Chromium Anodizing Tanks; and Steel Pickling— HCl Process Facilities and Hydrochloric Acid Regeneration Plants

On September 19 EPA  published their final hexavalent chromium rules: Federal Register / Vol. 77, No. 182 / P. 58220 / Wednesday, September 19, 2012.   Click on link to download:

EPA Final Hex Chrome Rule, 9-19-2012

The table below summarizes the rule.

  New Limits Previous Limits
Decorative Chromium Plating:
Existing Sources 0.007 mg/dscm 0.010 mg/dscm
New Sources 0.006 mg/dscm 0.010 mg/dscm
Chromic Acid Anodizing:
Existing Sources 0.007 mg/dscm 0.010 mg/dscm
New Sources 0.006 mg/dscm 0.010 mg/dscm
Hard Chromium Plating:
Existing Sources   (small) 0.015 mg/dscm 0.030 mg/dscm
New Sources (small) 0.006 mg/dscm 0.015 mg/dscm
Existing Sources   (large) 0.011 mg/dscm 0.015 mg/dscm
New Sources (large) 0.006 mg/dscm 0.015 mg/dscm

 

These are the lowest hex chrome emission limits in the world.   Many platers , especially decorative chrome platers, have been meeting the existing limits with PFOS fume suppressants.  However, the new rule  bans the use of fume suppressants containing >1wt% PFOS, because it is a long chain perfluorinated compound that is persistent in the environment (PFOS used to be used in manufacturing Scotchgard and similar fabric stain repellents, but those products were reformulated some years back).  There are now short chain perfluorinated compounds on the market that have been successfully tested for fume suppression in chrome plating baths.  EPA claims that the new limits can be met very inexpensively, merely by increasing the amount of fume suppression surfactant in the plating bath.  However, recent testing shows that merely reducing the surface tension of the bath does not in fact reduce emissions.  This leaves platers with the only option of installing far more expensive scrubbers, which will be difficult or impossible for typical small plating companies to afford, especially in the present economy.

The Graph above shows the vast difference that this rule will make to hex chrome emissions.  Simply reducing power plant emissions of CrVI to 99.5% of their current levels would have the same effect as utterly obliterating the coating industry (and driving out all the industries dependent on it, which is most of them).

For more information see the NAS F website discussion of the new rule at http://www.nasf.org/nasf-news.php.