40 CFR 63, Subpart N
As of September 21, 2015, additions of Perfluorooctane Sulfonic Acid and Perfluorooctane Sulfonate (PFOS) to any chromium electroplating and/or anodizing tank to control chromium emissions are prohibited.
Since September 2016, five non-PFOS fume suppressants were approved the California Environmental Protection Agency Air Resources Board for specified chrome plate operations (three products for decorative operations and chromic acid anodizing, and two products for hard chrome plating). These products, as well as their corresponding surface tension requirements, have been added to the list of already approved fume suppressants [PDF].
California’s requirements are more stringent than the federal rule (40 CFR Part 63, National Emission Standards for Chromium Emissions From Hard and Decorative Chromium Electroplating and Chromium Anodizing Tanks, Subpart N), so these approved suppressants can be successfully used in Indiana and other states seeking to comply with Subpart N. Additionally, the attached list includes company and product information for Non-PFOS based wetting agents/fume suppressants/surfactants [ZIP].
Emission Limit Reductions
Existing operations* must meet the following limits:
- Surface tension limits:
- Stalagmometer - 40 dynes/cm
- Tensiometer - 33 dynes/cm
- Regarding open & enclosed hard chromium electroplating tanks:
- Large** - 0.011 milligrams of total chromium per dry standard cubic meter (mg/dscm)
- Small - 0.015 mg/dscm
- Regarding decorative electroplating/chromium anodizing:
- 0.007 mg/dscm
Immediately upon startup, new operations must meet the following limits:
- Hard chromium electroplating:
- 0.006 mg/dscm
- Decorative Electroplating/Chromium Anodizing:
- 0.006 mg/dscm
* An existing operation is a hard chromium electroplating, decorative chromium electroplating or chromium anodizing tank of which construction or reconstruction commenced on or before February 8, 2012.
** A large hard chromium electroplating process includes potential rectifier capacity greater than 60 million ampere-hours per year. It is only significant for an existing operation.
Testing Requirements for Chromium Emissions
If a facility completed its performance test for chromium emissions after January 25, 1995 and those results meet the lower limits, that facility is not required to re-test. However, if the test occurred prior to January 25, 1995, the facility is required to re-test.
Recordkeeping
The fume suppressant manufacturer and product name records are now required in addition to maintaining surface tension measurement and wetting addition records.
Best Management Practices (BMP) Requirements
The following BMPs must be added to your Operations and Maintenance (O&M) Plan and put into practice:
- Store & transport substances utilized within plating tanks in closed containers. These containers should be stored within an enclosure.
- Utilization of preventive measures to preserve the rinse bath such as drip trays or contain and return systems.
- Collect and treat bath solution having drained or dripped from parts.
- Removal of excess solution over the plating tank.
- Separate the plating operation from buffing, grinding, and/or polishing using a barrier (e.g., plastic strip curtains).
- Begin cleanup within one (1) hour of spill if not within a containment area.
- Clean surfaces including storage areas, open floor areas, and walkways near tanks every seven (7) days or forty hours of operation, whichever is longer. This may be accomplished by choosing one (1) or more of the follow methods:
- HEPA vacuuming
- hand-wiping with damp cloth
- wet mopping
- rinse using potable water and collect in a treatment system
- application of non-toxic dust suppressant
Additional information concerning the amendments is summarized in Changes to 40 CFR 63, Subpart N [PDF].
For basic information on how to comply with the regulation, please review A Guidebook on How to Comply with the Chromium Electroplating and Anodizing National Emission Standards for Hazardous Air Pollutants [PDF], revised September 2004.
Resources
U.S. EPA Resources
- Chromium Electroplating NESHAP Information
- Fabricated Metal Products and Metal
- PFOS Chromium Electroplater Study, U.S. EPA Region 5 (September, 2009) [ZIP]