Internal Combustion (IC) Emergency Engines

The information on this page will assist in the completion and submittal of an application for each emergency engine. Each section of the page contains important information needed to submit an application.

Internal combustion engines used for emergency purposes including engines driving backup generators or fire suppression water pumps emit air contaminants including oxides of nitrogen, carbon monoxide, volatile organic compounds, oxides of sulfur, particulate matter and toxic air contaminants. Engines operated at stationary sources with brake-horsepower ratings of 50 bhp or greater require a permit to operate.

Emergency engines can operate on a variety of fuels including diesel, natural gas or propane. Emergency engines include those that are used only in emergency situations with limited operation allowed for maintenance and testing purposes. If the engine will be used for other purposes such as being a primary source of power or operated as part of a demand response program, please complete application forms for a non-emergency engine.

Application forms tell us about your operation and allow us to permit your process. Accurate and complete information decreases processing time and helps avoid additional charges for unnecessary revisions. Please carefully review and complete the following forms. Also listed below are required attachments that need to be submitted with the application. You may contact the District with any questions.

General Application: Word PDF

Emergency Engine Supplemental Form Word PDF

(see here for help with exhaust raincaps)

Toxics Form: Word PDF

Required Attachments:

  • Plot Plan including stack location and nearby building dimensions
  • Manufacturer or EPA or CARB certified emission data
  • Engine specification/data sheet
  • Control equipment specifications (if applicable)
  • BACT analysis (if applicable)

The general and equipment specific application forms along with required attachments must be submitted with each application packet.

Emergency Engine applications may also be submitted online through Citizen Access. If you have not done so already, you will need to first create an account.

The correct fee, as shown in the table(s) below, must be submitted with your application in order for it to be accepted. Please note that the fees listed in these tables are estimated and the final fee may be more or less than this amount based on time and materials spent processing the application. The District maintains work records for this purpose.

Fee Table

Emergency Engine Application Fees

If you are unsure of the correct fee contact the District (see Assistance tab) to obtain an application fee estimate to confirm the fees required for application submittal. Please note that an additional fee may also apply depending on the method of payment. A breakdown of how the application fee(s) are determined can be seen here. Additional information can be found in District Rule 40.

How to Pay

These fees may be paid by check payable to "Air Pollution Control District" or by credit card (Visa, MasterCard, Discover, and American Express).

If you choose to email or fax your application and intend on paying with a credit card, ensure that you have obtained your fee estimate and have it in hand, and then after submitting the application, you must contact the District over the phone at (858)586-2600 to provide payment information.

Please note that credit card payments are assessed a transaction fee of 2.19% that is charged by the credit card provider.

Citizen Access
Select equipment type applications can now be submitted online.

Fax: (858) 586-2601

Permit Processing
10124 Old Grove Rd
San Diego, CA 92131-1649

The District will act on complete applications as soon as possible but at most within 180 days. The engineer assigned to your application will review it and contact you within 30 days of receipt to confirm that it is complete or request additional information. Typically permits are issued in about 60 days. More complex processes will take longer. Common reasons that applications may take longer than 60 days to evaluate include: the project is a complex project specifically at a major source, if the project requires a mandatory public notice period due to being installed within 1000 feet of a school or triggering the requirement for a air quality impact analysis (AQIA), if they do not initially pass a health risk assessment (HRA) or AQIA, if BACT is not proposed or complete BACT analysis is not submitted or for major sources if actual emission data is not included.

Ensuring your application is complete is the best way to reduce processing time. Complete emissions data is the most important factor in minimizing application processing time and iterative information requests. If you have any questions about what information is required, please contact the District using the information on the Assistance tab.

Sign up for Citizen Access to get up to date information on the status of your application.

Learn more about the permitting process and what to expect.

Best Available Control Technology

If a piece of equipment or a process emits more than 10 pounds per day of particulate matter (PM10), oxides of nitrogen (NOx), volatile organic compounds (VOC) or oxides of sulfur (SOx), the application must include a best available control technology (BACT) analysis. If you have questions or need assistance reference the contact information on the assistance tab. Please review District Rules 20.1 and 20.2.


District Rule 1200 applies to any new, relocated, or modified emission unit which may increase emissions of one or more toxic air contaminant(s). The proposed project must comply with Rule 1200. Proposed equipment may require toxics best available control technology (TBACT) depending on the project. Please review District Rule 1200 for further details.

Trade Secret

District rules address how information that is submitted to the District is managed. District Regulation IX contains District Rules 176 and 177. Please refer directly to these rules when submitting trade secret information. However, be aware that you will need to submit:

  1. You must indicate on the general application form that your submittal includes trade secret information to ensure that it is not inadvertently made publicly available.
  2. A letter disclosing the proprietary information. Ideally, this information should be separated from your application and clearly identifiable. This can be submitted electronically, and can be a separate submittal from the main application package.
  3. A letter for the  public record explaining why the information needs to be held as trade secret or is otherwise exempt from disclosure.

Applications submitted with incomplete material composition data due to failure to include proprietary information can significantly delay permit applications. In an effort to expedite the permit application process it is recommended that you contact the manufacturer or vendor of any proprietary materials that are used in the process and prepare the required letters as part of your application submittal.


In 1989, the California state legislature passed a law, AB 3205, designed to protect schoolchildren from hazardous air contaminants. The law, as currently written, requires the District to notify parents of schoolchildren, neighboring businesses and residents of all new or modified equipment that emits any hazardous air contaminant into the air which will be installed within 1,000 feet of a school site. The law also requires the District to consider any comments before authorizing construction. Please review your proposed location. If a school property boundary is located within 1,000 feet of the proposed emissions point, the AB3205 process will be initiated. This process requires a 30 day public comment period and the overall process will delay projects by at least six weeks.


Depending on the installation date, model year, stationary source emissions, fuel type and engine portability, the following state Air Toxic Control Measures (ATCMs), and/or federal New Source Performance Standards (NSPS) and National Emission Standards for Hazardous Air Pollutants (NESHAP) may be applicable to your emergency engines

ATCM for Stationary Compression Ignition Engines (Stationary ATCM) - Applies to stationary engines that combust diesel fuel. Common requirements of the Stationary ATCM include purchasing an engine certified to the correct model year standards, limiting testing and maintenance operation and keeping records of operation and maintenance. Please see the Compliance Advisory discussing records needed to document emergency use.

ATCM for Portable Engines (Portable Engines) - This rule applies to engines that combust diesel fuel and are considered portable under the rule. Typical engines subject to this rule include emergency backup generators that are stored in one location and moved around the same facility to provide backup power as needed or that are otherwise not eligible for a District or State portable registration. If you think your engine may be portable, please contact the District prior to submitting your application to ensure that the correct application type is submitted. Common requirements of the Portable ATCM include purchasing a current tier engine and meeting fleet averaging standards.

RICE NESHAP (ZZZZ) - This EPA rule applies to both spark ignition and compression ignition emergency engines. For most new emergency engines, requirements of this rule are superseded by more stringent state regulations. The District will evaluate your application and include any applicable requirements of this rule in an authority to construct. The District also has created applicability tables to help you determine how this rule affects your engine which can be found at the RICE NESHAP link under additional resources.

NSPS IIII - This EPA rule applies to new compression ignition engines. For most new emergency engines, requirements of this rule are similar to the requirements for the Stationary ATCM. The District will evaluate your application and include any applicable requirements of this rule in an authority to construct.

NSPS JJJJ - This EPA rule applies to new spark ignition engines. For most new emergency engines, requirements of this rule are minimal and may include purchasing a certified engine, limiting non-emergency operation and maintaining records.

The engineer assigned to an application will review the proposed equipment to determine the requirements of these regulations that may apply to the emergency engine and include them as conditions in your authority to construct.

District Rules

Several District rules may apply to your equipment. General rules that may apply to Emergency IC Engines include Rules 5051525354, and 62.

Equipment specific Rule 69.4.1 applies to emergency engines. If the engine is located at a major source, it may also be subject to Rule 69.4. A complete listing of the District's rules can be found here.

Calculation Procedures and Additional Resources

Equipment Calculation Procedures - This page contains procedures to be used for calculating emissions from this equipment that should be submitted with each application.

Use of these calculation procedures will aid in minimizing application review time and costs.  The correct emission factors should be selected from the list based on equipment. If available, manufacturer provided equipment specific emission data or source test results should be utilized before using default emission factors. Sources of all emission data used must be included as attachments to the application.

AP-42 - An alternative compilation of emission factors and calculation procedures prepared by the EPA that may be utilized by the District in some situations for some equipment types.

EPA Certification Information - This page contains spreadsheets with emission factors for engines certified by the US EPA. Data is available for most diesel engines and certified spark-ignition engines and can be looked up by model year and EPA engine family name.

CARB Executive Orders - Use this link to obtain emission factors for certified diesel engines from the California Air Resources Board (CARB). Data can be looked up by engine manufacturer, model year and EPA engine family name.

Stationary Engine Compliance Information - Contains useful information prepared by the District for staying in compliance with stationary engine permit requirements.

Forms and Compliance Policies - See this page for compliance related forms (including reporting form templates) and compliance advisories that may be relevant to your equipment.

RICE NESHAP (ZZZZ) and NSPS – See the Rule Development archive page for 2013 for additional guidance on determining applicable RICE NESHAP and NSPS requirements.

Call Duty Engineer
(858) 586-2600

District Small Business Assistance Program Coordinator
(858) 586-2650