Background

As part of the rule development process for Proposed Rule 1407.1 – Control of Toxic Air Contaminant Emissions from Chromium Alloy Melting Operations (Proposed Rule 1407.1), the South Coast Air Quality Management District (South Coast AQMD) sought additional emissions data for chromium alloy melting operations. With the assistance of the California Metals Coalition (CMC), two chromium alloy melting facilities voluntarily participated in source testing of their melting operations. South Coast AQMD and CMC agreed that: the facilities would remain anonymous; a third-party consultant would conduct the source testing with South Coast AQMD oversight; and South Coast AQMD would pay for the source tests.

Source Testing

The purpose of source testing was to confirm the formation of hexavalent chromium from chromium alloy melting operations, quantify toxic air contaminant emissions from chromium alloy melting operations, and assess the effectiveness of associated existing pollution control devices. In addition to source testing, the South Coast AQMD analyzed various materials from the metal melting process (i.e. raw material, baghouse catch, slag, final material, and casting sand) for multiple metals.

Source testing was completed at two facilities, Facility A and Facility C. A third facility, Facility B, went out of business prior to conducting the source tests. South Coast AQMD evaluated and approved the reports submitted by the third-party consultant for the source tests conducted. Source test results for both facilities demonstrated that hexavalent chromium emissions occur during the chromium alloy melting process and current filtration control technology used at these facilities substantially reduces hexavalent chromium and other toxic air contaminant emissions. Below are clarifications to the source test report evaluations and the source test reports and evaluations.

• Clarifications to Source Test Report Evaluations for Facility A and Facility C - July 30, 2020 (PDF, 239kb)

• Source Test Report for Facility A - September 4, 2019 (PDF, 127Mb)  
  • Source Test Report Evaluation for Facility A - February 7, 2020 (PDF, 6Mb)
• Source Test Report for Facility C - November 8, 2019 (PDF, 96Mb)     
  • Source Test Report Evaluation for Facility C - February 7, 2020 (PDF, 6Mb)

For inquiries about the Proposed Rule 1407.1 Source Testing, please contact Michael Morris, Planning and Rules Manager, at mmorris@aqmd.gov or (909) 396-3282.