Facility Risk Reduction Program

The Air District’s Facility Risk Reduction Program focuses on existing facilities that pose the highest health risks to nearby residents and workers. This program requires these facilities to implement technically feasible and economically reasonable risk reduction measures on significant sources of health risk.

The Air District’s Regulation 11, Rule 18: Reduction of Risk from Air Toxic Emissions at Existing Facilities requires existing facilities with health risks above risk action thresholds to either reduce those health risks below the rule’s risk action thresholds or implement Best Available Retrofit Control Technology for Toxics on all significant sources of health risks.

Facility Risk Reduction Implementation Plan

The Air District is conducting health risk assessments (HRAs) for existing facilities using the latest science to determine which facilities exceed the Rule 11-18 risk action thresholds and are therefore subject to the Rule 11-18 risk reduction requirements.

The Air District assigns prioritization scores to determine which facilities must undergo health risk assessment. The Air District determines the prioritization score for each facility during the annual permit renewal process. The prioritization score is calculated based on the toxic emission inventory for the site, health effects data for the air toxics emitted, and distances from the site to nearby residents and off-site workers. If a site’s prioritization score exceeds a prioritization score threshold, the Air District will conduct a health risk assessment for that site. 

The Air District previously released Rule 11-18 Implementation Procedures in 2020 and an Implementation Flow Chart in 2018, but the Air District has withdrawn these documents while it works on improvements to the Facility Risk Reduction Program.

Updates and Improvements to the Facility Risk Reduction Program

The Air District is making updates and improvements to the Rule 11-18 Facility Risk Reduction Program. A public workshop was held virtually on February 15, 2024 to discuss and gather comments on multiple items. These include a draft updated Rule 11-18 Implementation Procedures (IP) document and a Rule 11-18 Concept Paper. The Concept Paper is an initial step in the process of developing amendments to Rule 11-18. In the paper, the Air District discusses potential changes to the rule that may help expedite the emissions inventory review (a crucial step in developing HRAs), HRA process, and risk reduction plan (RRP) approval steps, as well as other changes that may improve implementation of Rule 11-18. Public comments were accepted on both the draft Implementation Procedures document and the Concept Paper through February 29, 2024.

The updated Final Implementation Procedures document is now available, along with a Response to Comments document for comments received on the draft Implementation Procedures and the rule amendments Concept Paper.

Signup for Information about the Air District Facility Risk Reduction Program.

Stakeholder Meetings

To ensure transparency during the implementation of Rule 11-18, the Air District will periodically hold meetings with interested stakeholders to explain procedures, answer questions, and provide information about the status of the emissions inventory reviews, health risk assessments, risk reduction plan reviews, and installation of risk reduction measures. Stakeholders may also inform the Air District about educational or informational needs or public concerns about Rule 11-18 actions.

Dispute Resolution Panel

The Air District will convene a Dispute Resolution Panel to resolve disputes that may arise between industry, the public, and the Air District regarding Implementation of Rule 11-18 for a specific facility. The types of matters that this panel will handle include: inventory used, toxic air contaminant emission factors, emission calculation techniques, air dispersion modeling assumptions, the technical feasibility or economic burdens involved in compliance time demonstrations, or Best Available Retrofit Control Technology for Toxics determinations.

Additional Resources


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Last Updated: 3/11/2024