Document ID: EPA-HQ-OAR-2017-0685-0042
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2019-06-04T04:00Z

Background:

 EPA is required under the Clean Air Act (CAA) to conduct Risk and Technology Reviews (RTR) of rules passed under the CAA every 8 years.  
 EPA is currently conducting the RTR for the Coil MACT, along with RTRs for approximately 20 to 30 other MACT rules.  
 The RTR schedule for the Coil MACT is as follows:
 Proposed rule published:  2/18
 Final rule published:  2/19
 In reviewing data, gathered from the National Emission Inventory and the Toxic Release Inventory for the coil coating source category, EPA noticed some apparently anomalous data that did not seem congruous with how coil coating lines and processes operate.  
 It is beneficial for all parties, including EPA and the coil coating industry, for the data that is being analyzed at the beginning of the RTR process to be accurate.  

Investigation:  

NCCA members and relevant committees discussed and investigated data related to three substances in the dataset that appear to be inaccurately represented:  Hexavalent Chromium, Naphthalene, and Cadmium.  Following is a summary of the results of these investigations and discussions:

 Hexavalent Chromium:  Several facilities from several different coaters appear to have reported release of Cr[+6] as an air emission.  This is contrary to how the coil coating process works.  The Cr[+6] is appearing in the inventories because coaters are reporting chromium compounds.  The inventory reporting process automatically assigns a portion of these compounds as being Cr[+6] when, in fact, no Cr[+6] is being emitted to the atmosphere.  In fact, no chromium of any sort is being emitted to the atmosphere.  

We consulted with some of the paint suppliers, who have an excellent understanding of the fundamentals of the coatings and processes used in coil coating, and they confirmed our understanding.  Chromium is not a volatile material at the baking temperatures used in the coil coating process.  Chromium will not volatilize in the ovens, which operate at temperatures far below the boiling point of Chromium, which is almost 5000°F. 

 Naphthalene:  Facilities and coaters appear to be reporting release of naphthalene.  While  naphthalene may be present in some of the aromatic solvents that are sometimes used in the coil coating process, any residual naphthalene is handled in the ovens and thermal oxidizers that have been installed to handle VOCs.  Again, it seems likely that the inventory reporting process and inaccuracies arising from that process is the cause of the error.

 Cadmium:  A coater appears to have reported emissions of cadmium.  NCCA staff discussed the matter with a representative from the coater that reported the cadmium.  The representative investigated and informed staff that the cadmium was reported erroneously by a consultant that used to work for the coater.  The coater representative confirmed that no cadmium is currently used, and that no cadmium has been used for some time.