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Warehouse Indirect Source Rule (ISR)
The Air District is developing ideas for a possible rule that would reduce air pollution from warehouse operations. This page has updates on where that work stands, upcoming meetings, and related materials.
The Air District has published a Warehouse ISR Concept Paper to support early public discussion. To view or download the documents, please click on the links below.
- Request for Comments - Warehouse ISR Concept Paper
- Warehouse ISR Concept Paper Flyer
- Warehouse ISR Concept Paper: Exploring an Indirect Source Rule for Warehouses in the Bay Area
Comments on the concept paper are requested by June 1, 2026 at 5:00 PM. Comments may be submitted via email to ruledevelopment@baaqmd.gov and written comments may be submitted to the address listed at the bottom of this webpage.
Overview
An Indirect Source Rule (ISR) addresses air pollution by regulating facilities whose operations attract significant mobile-source emissions, such as heavy-duty trucks. Under this framework, the Air District regulates the facility operations that attract this activity, rather than regulating vehicles and equipment directly. Warehouses can generate frequent truck activity and associated emissions of particulate matter (PM), including diesel particulate matter (diesel PM), as well as nitrogen oxides (NOx).
Staff is exploring whether a Warehouse ISR could help the region meet air quality goals while also reducing pollution exposure in communities that are already more heavily impacted, including AB 617 communities.
Previous Committee Updates
Air District staff has provided several informational updates to the Stationary Source Committee as part of the early exploration of a potential Warehouse ISR. These updates were presented on March 13, 2024, September 11, 2024, November 13, 2024, and March 12, 2025, covering initial scoping, review of ISR programs adopted by other air districts, screening-level emissions analyses, and early regulatory concepts.
Materials from these prior Committee meetings are posted below.
Concept Paper
The Air District has published a Warehouse ISR Concept Paper to support early public discussion. The paper does not propose a final rule or identify a preferred approach. It shares preliminary ideas, lays out key tradeoffs, and invites public input to help shape any future rulemaking.
The paper covers:
- Which warehouses might be covered, including options based on facility size and location
- Phased and adaptive implementation approaches
- Different ways warehouses could meet their obligations, such as choosing from a list of approved actions or meeting a specific pollution-reduction target
- A focus on reducing particulate matter, particularly in impacted communities
- Reporting requirements to support tracking, enforcement, and program refinement
- Potential use of mitigation fees and locally focused incentive programs
Engagement and Next Steps
Starting in summer 2026, staff plans to hold public workshops and targeted meetings with community-based organizations, industry, labor, local governments, and other interested parties to further discuss and refine the concepts.
The Air District is accepting public comments on the Warehouse ISR Concept Paper through June 1, 2026. Written and/or email comments may be submitted to the addresses below:
Via e-mail at:
ruledevelopment@baaqmd.gov
Or via mail at:
Rule Development
Bay Area Air Quality Management District
375 Beale Street, Suite 600
San Francisco, CA 94105
Meetings, Workshops and Events
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Last Updated: 15/04/2026