Prompted by concerns over elevated air monitoring levels of hexavalent chromium in a southern California neighborhood, the South Coast Air Quality Management District (SCAQMD) is expected to propose revisions to its Rule 1469 – Hexavalent Chromium Emissions from Chrome Plating and Chromic Acid Anodizing Operations and Rule 1426 – Emissions from Metal Finishing Operations.
Local air officials have indicated that hexavalent chromium levels of more than 0.2 nanograms per cubic meter would pose unacceptable risks to human health. AQMD has already required one metal finishing shop to cease operations for exceeding 1 nanogram of hexavalent chromium per cubic meter at air monitors at the property boundary.
Focus is on Fugitive Emissions
The AQMD staff stated that they are concerned primarily about fugitive emissions from plating operations, rather than emissions from stacks, scrubbers and other control devices. To address the fugitive emissions from plating shops, AQMD may add the requirements below to the current rules for chromic anodizing and chrome plating operations.
- Monitoring on the premises using multiple monitors ($5000 each) with immediate abatement when levels exceed acceptable risk thresholds
- Total enclosures for plating and anodizing operations
- Buildings with negative air pressure
- Controls and/or covers on all tanks that are heated or agitated and may contain hexavalent chromium, including sealer and rinse tanks
- More stringent controls on abrasive blast cabinets and grinding operations
- New housekeeping requirements, including:
- Daily vacuuming of floors with a HEPA vacuum that is emptied in a clean room environment
- Daily cleaning of flat surfaces and wall
- Cleaning of roofs two times per month
Expansion to Other Metals
AQMD is also considering applying similar requirements for metal finishing operations pursuant to Rule 1426 to control fugitive emissions of other metals such as cadmium, lead, nickel, zinc and tin.
AQMD has indicated that it expects to issue the proposed rule by July 2017 and finalize it by the end of 2017. The industry is concerned that it may not be technologically or economically feasible to meet the proposed revisions. California state industry leaders and NASF representatives have met with AQMD officials this month. The industry is now in the process of evaluating options to address this significant and precedent-setting challenge to finishing operations in the region and beyond.
To view a summary of the pending regulatory actions from South Coast air regulatory officials, please click here.
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