Shredders and VOC Emissions
Metal shredding operations have the potential to emit volatile organic compounds (VOCs) and depending upon the amount emitted have the potential to trigger regulatory and/or permit requirements under the Clean Air Act (CAA) and associated state regulations.
VOC Emissions Guidance for Metal Shredders
ISRI’s “VOC Emissions Guidance for Metal Shredders” (December 2023) was prepared by ALL4, LLC. It provides general guidance to operators when calculating VOC emissions from metal shredders, as well as an overview of Clean Air Act (CAA) air permitting requirements associated with VOC emissions and ]a discussion of VOC stack testing methods. The document is targeted to the shredder community, particularly company and facility resources that are responsible for compliance with federal, state, and local air quality regulations. Site-specific practices and conditions at shredder operations can vary, and differences in operating practices may influence how VOC emissions are calculated for individual facilities. ISRI recommends that shredder operators consult with qualified environmental professionals (e.g. lawyers and/or consultants) that are familiar with state and local VOC air permitting requirements for specific shredder locations to address shredder emissions permitting and testing considerations.

The Guidance document identifies operational variables that could affect emissions from metal shredding operations, including feed composition. It is the result of a review of available VOC emissions test reports from the U.S. EPA , state regulatory agencies, and shredder operators. A total of 21 VOC testing programs at 15 different shredding facilities were compiled and evaluated, representing the diversity of shredding in the U.S.

The emissions factors contained within the report reflect a current and comprehensive review of available metal shredding VOC emissions data and therefore replace should be used in lieu of the metal shredder VOC emissions factors included in the 1996 Versar Title V Applicability Workbook. The Versar Report reflected the industry’s understanding at the time of its publication that shredder VOC emissions were negligible. The guidance regarding metal shredder VOC emissions factors provided in the Versar Report is no longer supported by ISRI.


David L. Wagger, Ph.D.
Chief Scientist
Director of Environmental Management
(202) 662-8533

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