The Oregon Department of Environmental Quality (Oregon DEQ) is requesting written comments on proposed air contaminant discharge permit (ACDP) attachments for emergency engines by December 5, 2025, at 5 pm. The ACDP Attachments will be applicable for the following cases:

1. Facilities that hold a General, Simple, or Standard ACDP and
   1. Are installing or have installed uncontrolled emergency engines that have an aggregated capacity for all emergency generators onsite of less than or equal to 3,000 hp, and
   2. Do not already have fuel specific engine requirements related to the proposed type of emergency engine(s) incorporated into the existing ACDP.
2. Facilities obtaining a General ACDP that also have an emergency engine(s) with an aggregated capacity of less than or equal to 3,000 hp.

Facilities interested in adding or replacing emergency engines to existing operations could apply for these attachments rather than completing the typical ACDP modification process. Permittees would have the opportunity to apply for the applicable Emergency Engine Attachment without undergoing a separate public comment period as typically required to add new regulations to an ACDP.

Click here to learn more about these proposed attachments and view the draft permits.

Reducing Administrative Burdens and Streamlining Authorization

A facility installing a categorically insignificant activity is exempt from notice of construction (NC) application requirements unless that activity is subject to National Emission Standards for Hazardous Air Pollutants (NESHAP) and New Source Performance Standards (NSPS) requirements [OAR 340-210-0205]. Stationary emergency generators and pump engines that have an aggregate rating less than or equal to 3,000 horsepower are considered a categorically insignificant activity and are subject to NESHAP and NSPS [OAR 340-200-0020(24)(uu)]. Therefore, if a facility is installing these units, an NC application is required. If the facility does not have the applicable NESHAP or NSPS requirements included in the existing permit, the NC will require permit modification to incorporate these requirements. Permit modification opens the permit and requires a public comment period.

The proposed Emergency Engine Attachments provide a method for facilities that hold a General, Simple, or Standard ACDP to include these activities in facility permitting through a streamlined issuance process due to the consistent requirements of the permit attachment that ensure compliance with NESHAPs and NSPS requirements. Since these attachments are in public comment, when assigned to a site they do not need to be publicly reviewed again. The ACDP Attachment will include all relevant requirements for any Emergency Engine; but likely only a portion of the listed requirements will apply to the facility specific equipment. As an example, the Attachment lists requirements for a spark ignition internal combustion engines (ICE) and reciprocating ICE – a requirement to change spark plugs would only be applicable for a facility with spark ignition ICE, though all requirements for reciprocating ICE will also be included in the Attachment.

What are the Permit Attachment Requirements?

There are several qualification criteria for a facility’s emergency generators to be eligible for these attachments including, but not limited to, those listed below.

1. The total horsepower of all emergency and fire pump engines at the source must not exceed 3,000 horsepower.
2. Emergency engines with pollution control devices are not eligible due to the lack of monitoring provisions in the attachment. If a facility would like to install an emergency engine with a pollution control device, the facility would need to apply for a new or modified permit rather than the proposed attachment.
3. The facility must not be a major source of hazardous air pollutants.
4. Only engines certified to meet federal emission standards are eligible. Tier 4 engines and those with pollution control devices are excluded.

In addition to the qualification criteria, the attachments also cover operational and maintenance requirements the facility must follow including those listed below.

1. Operational Requirements:
   1. Emergency engines may operate for maintenance and readiness testing for up to 100 hours per calendar year.
   2. If the engine burns diesel, ultra-low sulfur diesel must be used.
   3. If the engine burns gasoline, sulfur average standard of 10.00 ppm is required.
   4. The idle time and startup duration would also need to be minimized due to startup periods being limited to 30 minutes.
   5. Facilities cannot use emergency engines for non-emergency demand response, peak shaving, or financial arrangements involving power supply.
   6. Facilities cannot use the oil analysis program in NESHAP ZZZZ to extend the deadline an oil change must be completed by.
   7. Diesel-fired engines may not operate for more than two hours in any 24-hour period for testing purposes.
   8. Only one engine may be tested at a time, except when verifying startup systems for multiple engines.

2. Maintenance Requirements:
   1. Install non-resettable hour meter on each engine.
   2. Maintain and operate according to manufacturer’s written instructions.
   3. The oil and filter must be changed every 500 hours or annually, whichever comes first.
   4. Inspections of the air cleaner or spark plugs, whichever is applicable, must occur every 1,000 hours of operation or annually, whichever comes first. These must also be replaced as needed.
   5. Inspections of all hoses and belts must occur every 500 hours of operation or annually, whichever comes first. These must also be replaced as needed.

3. Recordkeeping and Reporting Requirements:
   1. Maintain records of malfunctions and corrective actions, maintenance activities, and hours of operation (categorized by emergency and non-emergency use).
   2. Submit annual report.

Oregon DEQ has included these requirements in a permit renewal or modification for sites with emergency generators except for the operational requirements on the time and number of engines allows to run listed in g and h above. Ensure that these are amenable for your facility operations if selecting this process.

What are the Next Steps Once the Attachment is Assigned?

The next steps after the permit attachment is assigned depend on the type of permit assigned, which matches the current ACDP of the facility.

General ACDP Attachment 32 would be valid for 10 years from the date of issuance. Likely, the General ACDP and General ACDP Attachment would expire at different times. If Oregon DEQ continues to use the Attachment, they will issue another public comment period to renew the permit for the next 10 years. Then the General Attachment holder that would renew their attachment through an application for reassignment using DEQ’s online system: Your DEQ Online.

Simple/Standard ACDP Attachment 01 would be valid for 5 years from the date of issue or until its conditions are incorporated into the facility’s Simple or Standard ACDP during renewal or modification, whichever is sooner. There is not currently a defined procedure for how the attachment would be incorporated into the permit.

If the facility currently holds a General, Simple, or Standard permit and the qualification criteria listed above are met, the proposed attachments can be used to streamline compliance for facilities updating or adding emergency generators. These attachments provide eligible facilities with a path to compliance for new generators that avoids waiting for a public comment period or full application review. If you have questions, please reach out to the Trinity Consultants Portland office or Beth Ryder for more information.