AB 2588 Air Toxics “Hot Spots” Reporting Explained
If your California facility releases substances on the state’s toxic air contaminant list, you may have a reporting obligation under AB 2588.
If your California facility releases substances on the state’s toxic air contaminant list, you may have a reporting obligation under AB 2588, the Air Toxics “Hot Spots” Information and Assessment Act of 1987. The program is administered through your local Air Quality Management District. The deliverable most facilities owe is an Air Toxics Inventory Report (ATIR): a facility-by-facility accounting of toxic air emissions that the district uses to identify, and in some cases publicly disclose, facilities posing measurable health risk to the community around them.
This piece explains what AB 2588 actually requires of a facility, how the toxics inventory differs from the routine Annual Emissions Report, when a Health Risk Assessment gets triggered (and why most facilities never hit that threshold), and what we typically see during the reporting cycle. For the broader picture, see our California air quality compliance guide.
What AB 2588 Is, and What It Is Not
AB 2588 is a toxics-focused reporting program layered on top of the regular air permitting and Annual Emissions Report (AER) framework. It is not a permit. It does not authorize you to operate equipment. It exists to give regulators and the public a complete picture of toxic air contaminant emissions from individual industrial and commercial facilities.
The program has three stages, though most facilities only see the first one:
Reporting.
Prepare and submit a toxics emission inventory (the ATIR).
Health Risk Assessment (HRA).
Required only when the district determines your reported emissions exceed prioritization thresholds. The HRA models offsite cancer and non-cancer health risk using CARB and Office of Environmental Health Hazard Assessment (OEHHA) methodology (commonly the HARP software).
Public notification and risk reduction.
If the HRA shows risk above district notification thresholds, the facility must notify nearby residents and businesses. Above higher thresholds, the facility must develop and implement a risk reduction plan.
Most reporting facilities live entirely in stage one. Stages two and three are uncommon and triggered case-by-case by the district, not on a fixed schedule.
Who Has to File
Applicability is determined by your local district, which uses a combination of factors: whether your facility appears on the district’s notified-facilities list, the toxic air contaminants you use or release, the equipment you operate, and proximity-sensitive considerations like nearby schools. Facilities most commonly pulled into AB 2588 include:
- Metal finishing and plating operations (especially those using hexavalent chromium, cadmium, nickel, or lead)
- Surface coating, painting, and printing operations using toxic air contaminants
- Combustion equipment (boilers, ovens, engines) above district thresholds
- Solvent cleaning and degreasing operations using listed solvents
- Chemical manufacturers, distributors, and warehouses storing or handling listed substances
A common point of confusion: if you already file an AER, that does not satisfy AB 2588. Both reports may be required, and they cover overlapping but distinct datasets. For the differences, see our AER vs. AB 2588 vs. CTR comparison.
What Gets Reported
The toxics inventory is built from the same operational data that drives an AER, with toxic-specific detail layered on:
- Material usage for every product containing a listed toxic air contaminant (paints, coatings, solvents, plating chemistries, fuels)
- Process data for each emission source (throughput, hours of operation, batch counts)
- Equipment-level emission factors from district guidance, CARB methodology, or stack-test data where required
- Abatement device efficiency for any scrubbers, baghouses, thermal oxidizers, or similar controls
- Stack and release parameters (exhaust point height, diameter, flow, temperature) used in any downstream dispersion modeling
- Site map showing each emission point, abatement device, and the location of receptors like nearby schools
When we walk a facility for AB 2588 work, the first questions we ask are about the chemistries inside the equipment, not the equipment itself. Two facilities running identical spray booths can have very different toxic emissions profiles depending on the coating system in use. The Safety Data Sheets (SDSs) and the actual usage records are where the report is built.
The Requirements at a Glance
| Trigger | What’s Reported | What Follows |
|---|---|---|
| Facility on district notification list, or operations match the district’s AB 2588 applicability criteria | Air Toxics Inventory Report (ATIR): facility-wide toxic air contaminant emissions, source by source, with supporting calculations | District review against prioritization thresholds |
| Reported emissions exceed district prioritization thresholds | Health Risk Assessment (HRA) using CARB / OEHHA methodology (HARP modeling), addressing offsite cancer and non-cancer health risk | District review against notification thresholds |
| HRA shows risk above district notification thresholds | Public notification of nearby residents and businesses; ongoing risk tracking | District review against risk-reduction thresholds |
| HRA shows risk above risk-reduction thresholds | Risk Reduction Plan: identified emission controls, implementation schedule, follow-up reporting | Ongoing district oversight and verification |
The thresholds for prioritization, notification, and risk reduction vary by air district. SCAQMD, BAAQMD, San Joaquin Valley APCD, and Sacramento each publish their own. The general structure above is consistent statewide.
Why the Schools Question Matters
If the nearest school is close to your facility, AB 2588 work gets more complicated, and more expensive. Districts treat schools as sensitive receptors. Proximity to a school can lower the threshold at which an HRA is required, expand who must receive public notification, and increase the scrutiny placed on dispersion modeling assumptions. The Air Permit Data Collection Sheet we use on every air permit and AB 2588 engagement asks for the name and distance to the nearest school specifically because that single fact can change the scope of the project.
Health Risk Assessments are not common deliverables in our practice. Most facilities never trigger one. When they do, the work shifts from desk-based reporting to modeling work, often using CARB’s HARP software, and from there to public-facing risk communication. We scope HRA work separately when it’s required.
How an AB 2588 Engagement Actually Runs
For facilities that have never filed before, or where prior filings are incomplete, we work the engagement in four phases:
Applicability and source survey.
Review the facility against the district’s AB 2588 program. Confirm whether the facility is required to report and identify every source of toxic air contaminants.
Data collection.
Gather SDSs, material usage logs, fuel records, throughput data, abatement device specifications, and the site map. Where existing records are gaps, we work with onsite staff to reconstruct usage from invoices and production logs.
Calculation and inventory build.
Apply district-approved emission factors and methodologies, source by source, with abatement efficiency credit where supported. The output is the ATIR submittal package.
Submittal and follow-up.
File with the district. Respond to district comments or requests for clarification. If the district returns a prioritization finding requiring an HRA, scope that work separately.
The most common gap we see on first-time engagements is incomplete material usage data. Facilities track what they buy, but few track what they consume by month and by process line. AB 2588 reporting forces that reconstruction. Once the underlying tracking is in place, repeat filings are much faster.
Where AB 2588 Sits Alongside Your Other Air Reporting
A facility that owes an ATIR almost always owes an Annual Emissions Report (AER) as well. The state’s air emissions reporting framework is also moving toward broader, more uniform annual reporting; see our overview of California’s converging annual emissions reporting for what’s changing and when.
Getting AB 2588 right is partly about the report itself and partly about the data foundation underneath it. The same SDSs, throughput records, and abatement device data that feed the toxics inventory also feed the AER, your air permit applications, and any future Health Risk Assessment work. We build that data foundation once and use it across the full reporting cycle.
Trusted throughout California
BSY started working with CDMS last year after our in-house EHS person departed the company. CDMS reviewed our existing operational permits as well as any additional Federal, State and Local regulations that could apply and helped us to create a comprehensive compliance calendar to track regulatory deadlines and submittal due dates. The CDMS team does an excellent job of tracking everything and can be relied upon to complete the forms accurately and assist with submittals, allowing me to focus on our business.
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