California Air Resources Board

There is currently no CARB-approved test method for acrolein from stationary sources. Until more is known about acrolein emissions, local air districts must determine on a case-by-case basis how they will implement their toxics programs.

On April 28, 2000, the ARB sent an advisory to the local air districts titled "Advisories to Limit Use of ARB Method (M430) Determination of Formaldehyde and Acetaldehyde in Emissions From Stationary Sources" which read:

Method 430 (M430) was last amended on December 13, 1991, by the Air Resources Board (ARB). M430 is based on collecting samples with impingers containing DNPH and analyzing the samples by HPLC. The method was developed to determine formaldehyde and acetaldehyde from stationary sources. In the intervening years, many studies have contributed to ARB staff's knowledge of aldehyde sampling and analysis. Unfortunately, all new information about M430 limits its applicability strictly to formaldehyde and acetaldehyde under certain conditions. Until an improved test method is identified, ARB has developed the following advisories warning against misuse of M430.

Advisories
First Advisory: Do not use M430 for the determination of any aldehyde(s) other than formaldehyde and acetaldehyde; especially, do not use M430 for the determination of acrolein.
Second Advisory: Any data or results, based on the use of M430 to determine acrolein, or aldehyde(s) other than formaldehyde and acetaldehyde, are suspect and should be flagged as non-quantitative wherever they appear.
Third Advisory: Any data or results, based on the use of M430 to determine formaldehyde and acetaldehyde in emissions containing over 50pmvd (parts per million volume dry) of oxides of nitrogen (NOx), are suspect and should be flagged as non-quantitative whenever they appear.

Background for the First Advisory: M430 has always been clear in its stated limitations regarding applicability. The statement of applicability limits its application to determination of formaldehyde and acetaldehyde in emissions from stationary sources. Nevertheless, statutory requirements for acrolein testing of emissions from stationary sources have led to the use of M430 for acrolein. ARB staff has warned against the use of M430 whenever contacted regarding such testing.
The technical limitation for M430 and acrolein involves the strong acid in the sampling train. Acrolein has a double bond that is rapidly degraded by acid. This leads to underestimation of the acrolein emissions. A partial "fix" for this problem was published as a circular by Air Toxics LTD. It involves mixing the sample with a strong organic solvent to pull the acrolein out of the acid, limiting the degradation of acrolein. This is to be done as soon as possible after sampling.
After further work, Air Toxics LTD. published a more comprehensive treatment of M430 problems with acrolein. According to their research, after 30 minutes in the sampling acid more than 60% of the sampled acrolein is lost. After one hour, 70% is gone. This is bad news since the typical sampling time is one hour. Based on this study, M430 cannot be used to determine acrolein.

Background for the Second Advisory: The preceding background for the first advisory casts serious doubt on any date or results using M430 for anything but the determination of formaldehyde or acetaldehyde. For example, the degree of acrolein degradation is not always 60% at 30 minutes, but varies from test to test unpredictably. An example of a set of results rendered void by the second advisory is the large M430 acrolein database compiled per the California "Toxic Hot Spots Act".

Background for the Third Advisory: The sampling acid in M430 is charged with a complexing agent before each test. The agent combines with aldehydes to prepare them for detection at the laboratory. If this combination does not occur, the formaldehyde or acetaldehyde cannot be quantified.
The complexing agent also combines with NOx. Any such NOx-agent combinations prevent aldehyde-combinations with that complexing agent. With enough NOx combinations, there will not be enough complexing agents for aldehyde quantification at the laboratory. For typical M430 sampling trains, this problem for aldehyde quantification occurs when the NOx concentration is 50ppmvd or higher.

There is currently no ARB-approved test method for acrolein from stationary sources. Until more is known about acrolein emissions, local air districts must determine on a case-by-case basis how they will implement their toxics programs. Additional information, including a research report that describes what we do know about the existing test methods, and details about ambient acrolein measurements, is provided below.

Ambient Data

ARB's ambient acrolein monitoring data, and test methods;

U.S. EPA's ambient method for aldehydes: TO-5

Additional Acrolein Information on Test Methods in Development

ARB's Acrolein Research Report - MSWord (124k)
Data summary - PDF

Draft Modified Stationary Source Test Method CARB 430 - MSWord (38k)
Ashland - Lawn Mower Emissions with Modified M430 - MSWord (2,309k)
Sucha Parmar - Retention Study of Acrolein with M430 Paper #1 - Paper #2
Japanese paper - hydroxylamine derivatization ( MSWord 108k)

ARB Test Method 430
Emission Inventory

This page is an archive of the previous version of the AB 2588 "Hot Spots" Guidelines Regulation. For the most recent Guidelines, visit "Hot Spots" Inventory Guidelines.

The Previous version of the Guidelines (Adopted by Air Resources Board on July 25, 1996; Effective July 1, 1997 through September 25, 2007)

• Regulation (CCR)
• Emission Inventory Criteria and Guidelines Report (Without Appendices)
• Appendix A: List of Substances | Excel
• Appendix B: Reporting Format and Instructions
• Appendix C: Facility Guideline Index
• Appendix D: Source Testing: Summary of Requirements
• Appendix E: Requirements for Facilities Emitting <10 tpy of Criteria Pollutants
• Appendix F: Criteria for Screening Risk Assessment
• Appendix G: List of Documents Incorporated by Reference

The AB 2588 "Hot Spots" fee categories, complexities, fee amounts, and description of each risk category are shown below. State fees are risk-based and assessed on an annual basis. The size of the facility (complexity) also affects the fee amounts in each risk category with larger (complex) facilities paying a higher amount than smaller (simple) facilities.

"Hot Spots" Facility Fee Category Flowchart

Use the following flow chart to determine the appropriate fee category for a given facility.

Background

California local governments have taken an active role in fighting climate change and reducing greenhouse gas (GHG) emissions. Local officials have expressed a need for a set of methodologies and data sources to inventory the GHG emissions from their government operations and to quantify the emissions impact of local government policies and programs.

ARB staff has partnered with the Climate Action Reserve (CAR), The Climate Registry (TCR), and Local Governments for Sustainability (ICLEI) to develop the Local Government Operations Protocol (LGOP) for GHG assessment. The LGOP is a reporting protocol (i.e. a set of common standards and calculation tools for estimating and reporting GHG emissions) that provides guidance on how to inventory GHG emissions resulting from government buildings and facilities, government fleet vehicles, wastewater treatment and potable water treatment facilities, landfill facilities, and other operations. The LGOP is available at the following link:

• Local Government Operations Protocol (version 1.1) [PDF-2,490 KB]

Tools

Landfill Emissions Tool

ARB staff has developed a spreadsheet-based tool for landfill emissions estimation. It implements the mathemetically exact first-order decay model of the 2006 IPCC guidelines. This tool is designed to estimate the fugitive emissions of a landfill that does not have a landfill gas collection system. If you have questions or comments about this tool please contact Mr. Larry Hunsaker.

• Landfill Emissions Tool Version 1.3 [Excel-523 KB]

Recycling and Composting Emission Reduction Factors

ARB staff has developed life-cycle based greenhouse gas emission reduction factors for recycling and composting. These factors are designed to provide local government officials, planners and other interested stakeholders with a reliable estimate for alternative waste management options. 

• Recycling Emission Reduction Factors [PDF-213 KB]
• Composting Emission Reduction Factor [PDF-153 KB]
• Carpet Recycling Emission Reduction Factor [PDF-630 KB]

For questions, contact: ghginventory@arb.ca.gov 

The California Toxics Inventory (CTI) currently provides emissions estimates by stationary (point and aggregated point), areawide, onroad mobile (gasoline and diesel), offroad mobile (gasoline, diesel, and other), and natural sources.

The CTI is developed by speciating ARB estimates of Total Organic Gas (TOG) and Particulate Matter (PM) for area, mobile, and natural sources using the most recent speciation profiles. Speciated emissions for each source category are then reconciled with reported stationary point source toxics data to establish a complete inventory.

Stationary sources include point sources provided by facility operators and/or districts pursuant to the Air Toxics “Hot Spots” Program (AB 2588), and aggregated point sources estimated by the ARB and/or districts. Areawide sources are those that do not have specific locations and are spread out over large areas such as consumer products and unpaved roads. Mobile sources consist of onroad vehicles such as passenger cars and trucks, motorcycles, busses, and heavy-duty trucks. Offroad sources include trains, ships, and boats. Natural sources like wildfires are also included.

Draft 2010 CTI Summary Table (November 2013) (Excel)

2008 CTI Summary Table - released on December 10, 2008 (Excel)

2006 CTI Summary Table - released on May 20, 2008 (Excel) (PDF)

2004 CTI Summary Table (Excel) (PDF)

Documentation (PDF)

Assembly Bill (AB) 2588 (Connelly), the Air Toxics "Hot Spots" Information and Assessment Act, requires facilities that are ranked as a high priority (see Prioritization) to submit a health risk assessment (HRA) to the air pollution control and air quality management districts (district). A risk assessment, as defined under the Air Toxics "Hot Spots" Act, includes a comprehensive analysis of the dispersion of hazardous substances into the environment, the potential for human exposure, and a quantitative assessment of both individual and population-wide health risks associated with those levels of exposure. The risk assessments submitted by the facilities are reviewed by the Office of Environmental Health Hazard Assessment (OEHHA) and approved by the district. In addition, the district may require facilities in the intermediate and low priority categories to also submit a health risk assessment.

OEHHA HRA Guidelines

Senate Bill 1731, which amends the "Hot Spots" Program, requires OEHHA to adopt risk assessment guidelines for the program using a full public review process. You can obtain a copy from OEHHA.

Hotspots Analysis and Reporting Program

The Hotspots Analysis and Reporting Program (HARP) is a software suite that addresses the programmatic requirements of the AB 2588 Air Toxics "Hot Spots" Program.  HARP incorporates the information presented in the 2015 Air Toxics Hotspots Program Guidance Manual for Preparation of Health Risk Assessments. HARP is divided into three programs: the Emissions Inventory Module (EIM), Air Dispersion Modeling and Risk Tool (ADMRT), and Risk Assessment Standalone Tool (RAST). HARP can be used by the air pollution control and air quality management districts (districts), facility operators and other organizations or individuals to promote statewide consistency, efficiency and cost-effective development of facility emission inventories and conducting health risk assessments. HARP can also be used for conducting health risk assessments used in other programs (e.g., facility permitting, CEQA reviews).

Risk Management Policy for Risk Assessment Using the Inhalation Pathway

This policy is presented in Appendix D of the document CARB/CAPCOA Risk Management Guidance for Stationary Sources of Air Toxics (July 23, 2015). CARB and CAPCOA established this policy through a public process with input from industry and environmental representatives. This policy uses the new risk assessment science included in the Office of Environmental Health Hazard Assessment (OEHHA) Guidance Manual (OEHHA Manual) while providing a reasonable estimate of potential cancer risk for use in risk assessments for risk management decisions. The individual Districts have the authority to decide how, or if, they will use this recommended policy in their programs. 

Consolidated Table of OEHHA/CARB Approved Risk Assessment Health Values

The Consolidated Table of OEHHA / CARB Approved Risk Assessment Health Values is a quick look-up table of all cancer potency values and noncancer acute, 8-hour, and chronic Reference Exposure Levels (RELs) that are available for use in the AB 2588 Air Toxics "Hot Spots" Program. The most current health values should be used for the development of a facility health risk assessment. For more information on the OEHHA Guidelines, see the OEHHA website. Users of this table are advised to monitor the OEHHA website for any updates to the health values. 

Review of Updated and Screening HRAs

In 1997, the staff of CARB, the OEHHA, and the districts collaborated to develop a streamlined process for the submittal and review of updated, and screening, health risk assessments (HRAs). That joint effort resulted in the development of a set of forms (see HRA forms Word | PDF) intended to accompany the submittal of updated, or screening, HRAs to the appropriate district and to OEHHA. There is also a list of the minimum data fields required when submitting an updated, or screening, HRA for those individuals that chose to not use the forms developed.

Industrywide Risk Assessments

CAPCOA, in cooperation with OEHHA and CARB, are developing three industrywide risk assessment procedures. The purpose of these industry specific assessments is to assist both the districts and facilities with the emission inventory and risk assessment requirements of the "Hot Spots" program (see Overview of "Hot Spots" Program).

Facilities which meet a specific set of requirements outlined in the law are candidates for an industrywide assessment. The requirements are focused on small businesses that are from the same industrial class, where individual compliance would impose severe economic hardships, and where emissions are easily and generically characterized.

Please refer to the Industrywide Risk Assessment List below to download a copy of a particular risk assessment or to get in contact with CARB or district staff person responsible for that guideline. 

Industrywide Risk Assessment Guidelines

Overview of the Air Toxics "Hot Spots" Act
"Hot Spots" Powerpoint Slide Presentation (Fall 2002)
"Hot Spots" Powerpoint Slide Presentation (2005)

AB 2588 -- Air Toxics "Hot Spots" Information and Assessment Act of 1987

Health and Safety Code:

1. H&S section 44340 - requires an inventory plan by August 1, 1989; and Section II.E. of the EIC&G Regulation (93300.5, title 17 CCR) - requires an inventory plan by August if requested by the district before January of that year.
2. H&S section 44340 (b) - requires the district to approve the inventory plan within 120 days.
3. H&S section 44341 - requires facility to submit an inventory report within 180 days.
4. H&S section 44343 - requires district to approve the inventory report within 90 days.
5. H&S section 44360(a) - requires the district to prioritize the facility within 90 days.
6. H&S section 44360(b) - requires facility to complete HRA within 150 days.
7. H&S section 44361 - requires OEHHA to review HRA within 180 days.
8. H&S section 44362(a) - requires district to review HRA within 1 year.
9. H&S section 44362(b) - requires facility to conduct public notification.
10. H&S section 44391(f) - requires facility to submit a risk reduction audit and plan within 6 months.
11. H&S section 44391(g) - requires the district to review the plan within 3 months; and H&S section 44391(a) and (c) - requires risk to be reduced within 5 years with option of an additional 5 years.

The AB 2588 Air Toxics "Hot Spots" Emission Inventory Criteria and Guidelines Regulation (Guidelines, or EICG Regulation) provides direction and criteria to facilities on how to compile and submit air toxics emission data required by the "Hot Spots" Program. The latest 2022 amendments to the EICG regulation were approved by the Office of Administrative Law and filed with the Secretary of State on March 21, 2022. The EICG effective date is March 21, 2022.

2022 Amendments to the EICG Regulation  

The California Air Resources Board (CARB) amended the EICG Regulation to ensure continued protection of public health by collecting more comprehensive emission data, provide CARB and the local air districts with a better understanding of stationary source emissions, enhance the public access to information on toxic pollutant emissions, and require the reduction of localized health risks at facilities that may present significant impacts. The 2022 amendments are also designed to support community-focused efforts at CARB to reduce criteria pollutant and air toxic emissions from California’s most disadvantaged communities.

2022 EICG Amendments Approved by OAL and Effective March 21, 2022

On November 19, 2020, the California Air Resources Board (CARB) adopted amendments to the proposed Air Toxics “Hot Spots” Emission Inventory Criteria and Guidelines (EICG) Regulation, and the Regulation for the Reporting of Criteria Air Pollutants and Toxic Air Contaminants (CTR). Based on public comment received, the Board directed CARB staff to consider additional modifications to the regulations prior to finalizing the revisions. Staff incorporated revisions to the EICG through a public "15-day" revisions process, including a workshop on February 11, 2021 (see below). The final 2022 EICG rulemaking package was approved by the Office of Administrative Law and filed with the Secretary of State on March 21, 2022.  The EICG effective date is March 21, 2022. Formal regulatory documents for the 2022 EICG amendments are available on CARB’s rulemaking website.

Unofficial “Clean” 2022 EICG Amendment Documents 

This unofficial version of the Air Toxics “Hot Spots” Emission Inventory Criteria and Guidelines (EICG) Regulation following this Disclaimer was produced by CARB staff for the reader’s convenience. CARB staff has removed the underline-strikeout formatting which exists in the Final Regulation Order approved by the Office of Administrative Law (OAL) on March 21, 2022, and included the full regulatory text for the regulation. However, the following version is not an official legal edition of title 17, California Code of Regulations (CCR), section 93300.5. While reasonable steps have been taken to make this unofficial version accurate, the officially published CCR takes precedence if there are any discrepancies. Documents relevant to the rulemaking process for this version of the regulation, including the Final Regulation Order, with underline/strikeout formatting showing additions and deletions to the regulation, is available on the CARB website here.

The unofficial “clean” versions of the EICG documents can be found at the links below:

Regulation (CCR)

• Emission Inventory Criteria and Guidelines Report (Sections I-XI) | Word
• Appendix A (List of Substances) | Excel | A-I | A-II | A-III | Notes
• Appendix B-I (Reporting Formats) | Word
• Appendix B-II (Reporting Forms) | Word
• Appendix C (Facility Responsibilities) | Word
• Appendix D (Source Testing) | Word
• Appendix E (Requirements for Smaller Facilities) | Word
• Appendix F (Screening HRAs) | Word
• Appendix G (Documents Incorporated by Reference) | Word

Other materials from the rulemaking process, including previous workshop presentations, are available below. 

Joint Webinar: February 11, 2021
Proposed 15-Day Changes for "Hot Spots" EICG & CTR

CARB staff hosted a webinar to discuss proposed 15-day changes (see above) to the AB 2588 Air Toxics "Hot Spots" Emission Inventory Criteria and Guidelines Regulation (EICG) and the Regulation for the Reporting of Criteria Air Pollutants and Toxic Air Contaminants (or CTR). The proposed modifications to EICG and CTR were presented in a joint webinar due to multiple common elements between the two programs.

During the workshop staff presented the proposed changes and answered questions about the changes. There is now a period for informal written comments to help refine the draft text prior to the official release of the proposed 15-day changes. Please submit comments via email by February 25, 2021.

• Presentation Slides
• Comments & Questions Submitted
• Video Recording of Webinar
• Workshop Notice
• Submit "Informal" Comments by 2/25/2021, to be used in preparing final 15-day modifications

"Informal" 15-Day Modification Materials for Review

1. Emission Inventory Criteria and Guidelines Report (proposed 15-day modifications)
2. Appendix A: Proposed List of Substances to be Reported (draft modifications)
3. Appendix C: Examples of Chemicals Expected by Process and/or Industry Sectors (draft modifications)
4. Appendix D:  Source Testing Requirements (draft modifications)
5. Appendix E: Requirements for Facilities Emitting Less Than 10 tpy of Criteria Pollutants (draft modifications)

Joint Webinar: September 30, 2020
"Hot Spots" EICG & CTR Proposed Amendments

CARB staff hosted a webinar to discuss proposed amendments to the AB 2588 Air Toxics "Hot Spots" Emission Inventory Criteria and Guidelines Regulation (EICG), as well as proposed amendments to the Regulation for the Reporting of Criteria Air Pollutants and Toxic Air Contaminants (or CTR). The proposed amendments to EICG and CTR were presented in a joint webinar due to multiple common elements between the two programs. Please see the materials below for additional information.

• Presentation Slides
• Comments & Questions Submitted
• Video Recording of Webinar
• Regulatory Documents including the Proposed Regulation Order and Staff Report
• Workshop Notice

July 29, 2020: Draft EICG Materials Available for Review and Comment 

The following draft materials are provided for review and comment prior to the publication of the formal regulatory materials at the end of September 2020. In order to allow sufficient time to fully consider your input, we request that you submit your comments via email by August 12, 2020.

Materials for Review

1. Phase-In Schedule Diagram: Illustrates the reporting schedule for industrial sectors subject to expanded applicability in the Criteria & Toxics Reporting Regulation (CTR) and the EICG Appendix A new chemicals list
2. Emission Inventory Criteria and Guidelines Report (draft sections I to V of regulatory text proposed amendments)
3. Appendix A: Proposed List of Substances to be Reported (updated draft)
4. Appendix C: Examples of Chemicals Expected by Process and/or Industry Sectors (updated draft)
5. Appendix D and EICG Section IX: Source Testing (discussion of proposed revisions for source testing)

We plan to post additional materials for informal review as they become available. Please note that comments received prior to the start of the formal review period on October 2, 2020, are not part of the official rulemaking record; however, they will be considered and evaluated as we continue our work on developing the proposed amendments to the regulation.

For questions about the posted materials please contact Anne Klein, Air Pollution Specialist, or Steve Zelinka, Manager, Toxics Inventory and Special Projects Section.

Webinar: April 30, 2020
Discussion of Proposed Amendments to the EICG Regulation 

CARB held a webinar on April 30, 2020, to discuss the proposed amendments to the EICG Regulation. The materials presented at the webinar, along with an audio recording and written questions and comments submitted during and after the webinar are available below.

Webinar Materials

• Presentation Slides
• Comments & Questions Submitted
• Video Recording of Webinar
• Webinar Notice
• Opening Message from Assemblymember Cristina Garcia
• Additional Supporting Documents
  1. Appendix A: Proposed List of Substances to be Reported (workshop draft)
  2. Appendix C: Examples of Chemicals Expected by Process and/or Industry Sectors (workshop draft)
  3. Appendix E: Proposed Requirements for Smaller Facilities (workshop draft)
  4. Scientific Review Panel: Interim Findings Regarding the Chemical List

For questions about the webinar, please contact Anne Klein, Air Pollution Specialist or Steve Zelinka, Manager, Toxics Inventory and Special Projects Section.

Subscribe for updates to Air Toxics "Hot Spots" Criteria and Guidelines notifications.

Scientific Review Panel Evaluation

As part of our preparations for amending the current regulation, CARB staff solicited support from the Scientific Review Panel (SRP) in evaluating the proposed updates to the chemical substances list in Appendix A of the regulation. The following documents were provided to the SRP for their review:

SRP Chemical List Introduction: Transmittal document requesting SRP review of the proposed updates.

Existing Appendix A: A list of the substances in Appendices A‐I to A‐III of the current regulation.

Master List of New Proposed Substances: A list of over 800 new substances proposed for addition to Appendices A-I to A-III, along with a list of over 500 substances that were evaluated but are not being proposed for inclusion.

New Proposed Appendix A‐I by Category: This is the subset of the Master List: new substances proposed for addition to Appendix A‐I, grouped into the following eight categories:

1. Carcinogens
2. Developmental and Reproductive Toxicants
3. Pesticides
4. Metals
5. Other Inorganics
6. Pharmaceuticals
7. Neurotoxins
8. Other

Master List of New Proposed Substances: An Excel version of the Master List of new substances proposed for addition, separated into tabs for Appendices A‐I, A‐II, A‐III, and substances that were evaluated but are not being proposed for inclusion.

Prior Regulation (approved by OAL on August 27, 2007)

(2007 EICG) Regulation (CCR)

• Emission Inventory Criteria and Guidelines Report (Sections I-XI) | Word
• Appendix A (List of Substances) | Excel | A-I | A-II | A-III | Notes
• Appendix B-I (Reporting Formats) | Word
• Appendix B-II (Reporting Forms) | Word
• Appendix C (Facility Responsibilities) | Word
• Appendix D (Source Testing) | Word
• Appendix E (Requirements for Smaller Facilities) | Word
• Appendix F (Screening HRAs) | Word
• Appendix G (Documents Incorporated by Reference) | Word

(2007 EICG) Formal Rulemaking Documents

The Emission Inventory Criteria and Guidelines are used for preparing emission inventory plans and reports to develop site-specific inventories of air emissions of toxic substances. The Guidelines do the following: 1) specify which facilities are subject to air toxics emission inventory reporting and update reporting; 2) specify information a facility operator must include in a facility's air toxics emission inventory plan and inventory report; 3) identify specific classes of facilities that emit less than ten tons per year of criteria pollutants that are subject to the Hot Spots program and specify their emission inventory reporting requirements; 4) specify source testing requirements, acceptable emission estimation methods, and the reporting formats to be used; 5) establish groups of the substances to be inventoried; 6) designate facilities into levels for purposes of update reporting, based on prioritization scores, risk assessment results, or de minimis thresholds; 7) exempt "low level" facilities from further update reporting unless specified reinstatement criteria are met, and specify the update reporting requirements for other facilities; 8) specify information a facility operator must include in a facility's update to the facility emission inventory; and 9) include provisions for integrating Hot Spots reporting with other district programs if specified criteria are met.

The Guidelines are organized into sections which address related requirements. Sections are included on applicability, facility removal from the program, update categories, reporting requirements, and source testing requirements.

The appendices to the Guidelines are useful documents which may be downloaded separately from the Guidelines Report. Appendix A includes three lists of substances in the program: those for which emissions must be quantified; those for which production, use, or other processes must be reported; and those which need not be reported unless manufactured by the facility. Appendix B contains reporting formats and instructions. Appendix C is the Facility Guideline Index which specifies responsibilities for specific facility classes. Appendix D indicates source testing requirements. Appendix E specifies requirements for classes of facilities emitting less than 10 tons per year of criteria pollutants. Appendix F contains the criteria for inputs for risk assessment using screening air dispersion modeling. Appendix G is the list of documents which have been incorporated into the Guidelines by reference.

Previous drafts of Guidelines Regulation

2022 Frequently Asked Questions (FAQs) | Word (January 2025)

2007 Frequently Asked Questions (FAQs) | Word (September 2007)

Air Districts Hot Spots Annual Reports

CARB's California Air Toxics Emission Factor (CATEF) Database

Air District Memo: Interpretation of the Emission Inventory Criteria and Guidelines Regulations Requirements (September 1989)

1989 Technical Guidance Document for EI Guidelines

More Information about Appendix A - List of Substances

Addendum to TGD for Wood Fired Boilers

This page documents the ARB's efforts to QA the CEIDARS toxics data.

1. QA of Toxics Data
   As part of our emission inventory data review, ARB staff has identified several facilities with toxic emissions in our CEIDARS inventory that we would like district staff to review for accuracy. This list was compiled in part by identifying the highest prioritization (potency-weighted) scores for each toxic in our point source inventory. We also identified several facilities that emit significantly more of a listed toxic than any other facility in California. Please confirm the accuracy of the emissions data if possible, and let us know if there are any problems with the data.
   
   Download the short list of facilities for district review (80k) 
   
   Background Information:
   Top potency-weighted emissions
   Top toxics emissions (by mass)

2. Deleted Pollutants
   The following pollutants have been removed from the CEIDARS Pollutant Table:

   We used to use these POLs...		Now we use these POLs.
   Old POL (No longer in CEIDARS)	POLN (of Old POL)	Correct POL (in CEIDARS)	POLN (of Correct POL)
   1015	[D] Arsenic compounds (inorganic)	1016	Arsenic compounds (inorganic)
   1021	[D] Beryllium compounds	7440417	Beryllium
   1045	[D] Cadmium compounds	7440439	Cadmium
   1067	[D] Copper compounds	7440508	Copper
   1105	[D] Fluorocarbons (chlorinated and brominated)	1104	Fluorocarbons (chlorinated)
   1120	[D] Hexachlorocyclohexanes	608731	Hexachlorocyclohexanes
   1130	[D] Lead compounds (Inorganic)	1128	Lead compounds (inorganic)
   1132	[D] Manganese compounds	7439965	Manganese
   1133	[D] Mercury compounds	7439976	Mercury
   1145	[D] Nickel compounds	7440020	Nickel
   1170	[D] Selenium compounds	7782492	Selenium
   1204	[D] Toluene diisocyanates	26471625	Toluene diisocyanates
   1210	Xylenes	1330207	Xylenes (mixed)
   1211	[D] Zinc compounds	7440666	Zinc
   3333393	[D] Nickel carbonate	3333673	Nickel Carbonate
   124403	[D] Dimethylamine	dropped from CEIDARS
   1040	[D] Bromine Compounds (inorganic)	dropped from CEIDARS

   
   [D] Acetone will be retained in CEIDARS.
    
3. Missing Criteria and Toxics Emissions
   Most facilities in CEIDARS have both criteria and toxic emissions. However, some large (>10tpy) criteria pollutant facilities do not have corresponding toxics data, and some facilities with large (>10tpy) toxics do not have corresponding criteria pollutant data. Each of these lists is linked below. [Note: Some facilities are exempt from reporting toxics because their risk assessment is less than 1 per million. The HRA score for these facilities must be reported in CEIDARS.]
   Facilities with No Emissions
   Criteria Pollutant Facilities Missing Toxics Data
   Toxics Facilities Missing Criteria Pollutants
    
4. Hexavalent Chromium Emissions
   Highest Hex Chrome Sources for 2004-2006
    
5. FEE_CAT
   The Fee_Cat Code in the Facility Table indicates the status of the facility (low, medium, or high risk) using letter codes A-G, with a few additional codes for exempt facilities. Fee_Cat codes are being corrected, based on AB 2588 State Fee information.
    
6. Diesel in CEIDARS
   Diesel emissions should be reported using toxics emittent ID# 9901, and using criteria pollutant PM10 with appropriate SCC Codes. When the criteria and toxic emissions are not equal, it is difficult for ARB to determine which emissions are correct. Our analysis is here: Diesel
    
7. Chrome Platers
   ARB has compiled updated emission estimates for chrome platers. ARB staff is reconciling the data for South Coast, which includes more than 75% of all chrome platers in CA. Chrome Platers in SCAQMD
    
8. Comparison by SIC, POL, and SCC
   ARB compared the number of different SIC Codes, Pollutants, and SCC Codes in CEIDARS from 2001 through 2004 to identify trends in the toxics data. The data clearly shows that districts are submitting more data on gasoline service stations; more sources are reporting benzene and formaldehyde emissions (primarily from South Coast's AER); and more diesel engines are being reported, along with a higher percentage of generic classifications for some processes (SCC Codes). More information is here: by SIC - by Pollutant -- by SCC (Top20)
    
9. Comparison with TRI data
   All of the top emitters in the U.S. EPA's TRI 2005 Facility Inventory reported criteria pollutants in the 2004 CEIDARS Inventory. Some toxics data appears to be inconsistent. TRI data
    
10. Location Data
    ARB staff is verifying location data of facilities in CEIDARS, with an emphasis on large emission sources, including facilities in CHAPIS (Community Health Air Pollution Information System). New procedures are in place to automate this process each year. Some facility locations may need to be verified by districts. More information will be provided here soon.
     
11. Potency-weighted Toxics
    A Rank-Ordered List of Toxics has been compiled, which shows the highest potency-weighted scores for 1996, 2001, 2004, 2005, and 2006.
     
12. Air Toxics Inventory of all sources (Point, Areawide, On-Road Mobile, Off-Road Mobile, and Natural)
    (Draft -- double counting not yet addressed)
     
13. Emissions comparison between 2001 and 2005 emissions data.
     
14. Linking all prioritization scores and risk data with all CEIDARS facilities.
    ARB is considering asking districts to provide prioritization scores for all facilities in CEIDARS so we can better track facilities... Right now we only have prioritization scores for facilities that pay State fees. This includes new facilities with a high prioritization score (but no HRA), and facilities with an HRA >1 per million. The data will be reflected in CEIDARS as either a high priority, or not high-priority facility (the score won't actually be visible).

CARB offers support for small and medium sized business to assist them in their efforts to reduce their toxic emissions and risk. As part of this effort, CARB has developed risk reduction audit and plan guidelines pursuant to the requirements of Senate Bill 1731 (Calderon, 1992). The law requires facilities which are determined to present a significant risk to conduct a toxic risk reduction audit and develop a plan to implement measures to reduce that risk. Each district is responsible for establishing the risk value at which facilities must conduct a risk reduction audit and plan. CARB is directed to assist smaller businesses in these efforts.

The risk reduction audit and plan guidelines provide industry with a menu of risk reduction compliance options. CARB has four source-specific risk reduction guidelines as shown in table below. In addition, a General Guidance Document is available to help those facilities not covered by the specific guidelines. Please refer to the table below to download a copy of a particular risk reduction guideline. 

Risk Reduction Audits and Plans