Public Notice
Mississippi Environmental Quality Permit Board
P. O. Box 2261 | Jackson, MS 39225
515 East Amite St. | Jackson, MS 39201
Telephone No. (601) 961-5171

Public Notice Start Date: September 24, 2025	MDEQ Contact: Chappell Ford

Enchanted Rock LLC, Entergy ERDC-EGUs, located at Whitten Street, in Vicksburg, MS, (601) 634-5318, has applied to the Mississippi Department of Environmental Quality (MDEQ) for the following permitting action(s):  Initial Synthentic Minor Operating Permit (SMOP), Air Ref. No. 2780-00119. The applicant's operations fall within SIC Code 4911.  A Statement of Basis has been prepared that contains a discussion of the decision-making that went into the development of the permit and provides the permitting authority, the public, and other government bodies a record of the technical issues surrounding issuance of the permit. The Statement of Basis also addresses any changes to emissions and/or discharges resulting from any modification of the facility.  
Enchanted Rock is proposing to build and operate Entergy ERDC - EGUs facility (ERDC) in Vicksburg, Warren County, Mississippi. Enchanted Rock will provide a non-emergency power source for Entergy. This synthetic minor operating permit application submittal is to authorize the operation of 16 natural gas-powered spark ignition reciprocating engines.  There are currently eight (8) existing emergency generators near the location of the planned eight (8) new engines. 

Enchanted Rock constructed eight (8) natural gas fired spark ignition emergency engines in 2021. The potential to emit (PTE) for those eight engines was based on 500 hours/year and 100 hours/year.  The PTE for Engines 1-8 (AA-001 through AA-008) were below the threshold to require a construction and operating permit in the intervening years. Permits were not required for Engines 1-8 to operate as emergency engines. Enchanted Rock plans to construct an additional eight (8) natural gas fired spark ignition engines (AA-009 through AA-016). The PTE for those 8 engines is below the threshold to require a permit to construct and qualify under the de minimis modification definition in 11 Miss. Admin Code Pt. 2, R. 2.1.C.(5)., where the increase in emissions is less than three-fourths (3/4) of the threshold for a major modification (250 tpy). Therefore, a construction permit for the eight (8) new engines is not required.

After issuance of the SMOP, Enchanted Rock plans to run the original eight (8) emergency engines as full-time, non-emergency engines alongside the eight (8) new engines. Therefore, the facility has the uncontrolled potential to emit (PTE) for all 16 engines of 201 tons per year (tpy) of Carbon Monoxide (CO). The facility does not have the uncontrolled PTE to emit more than 100 tpy of any other Criteria Pollutant and less than 25 tpy of total hazardous air pollutants (HAPs) and less than 10 tpy of any individual HAP. The facility has requested a run time limit of 4,250 hours per generator per year to reduce the PTE of CO to less than 100 tpy, the Title V threshold, for the 16 engines. 

The staff of the Permit Board has developed this draft permit based on information submitted to the Permit Board by the applicant, appropriate State and Federal agencies and other interested parties. The staff of the Permit Board is soliciting all relative information pertaining to the proposed activity, including public comment, to ensure that the final staff recommendation on the draft permit complies with all State and Federal regulations. Public review and comment on the draft permit and supporting documentation is an important element in the staff evaluation and resulting recommendation to the Permit Board. The draft permit conditions have been developed to ensure compliance with all State and Federal regulations but are subject to change based on information received as a result of public participation.
Persons wishing to comment upon or object to the proposed determinations are invited to submit comments in writing to Chappell Ford at https://www.mdeq.ms.gov/Ford-Chappell/ or to the Permit Board address shown above, no later than the end of the thirty (30) day public notice. All comments received by this date will be considered in the formulation of final determinations regarding the application(s).  A public hearing will be held if the Permit Board finds a significant degree of public interest in the proposed permit(s). Persons wishing to request a public hearing may do so by submitting that request in writing to Chappell Ford at https://www.mdeq.ms.gov/Ford-Chappell/ or to the Permit Board address shown above.  The Permit Board is limited in the scope of its analysis to environmental impact.  Any comments relative to zoning or economic and social impacts are within the jurisdiction of local zoning and planning authorities and should be addressed to them.
Additional details about the application, including a copy of the draft permit, are available by writing or calling the Public Records Request Officer at the above Permit Board address and telephone number or by completing the form at the following website:  https://www.mdeq.ms.gov/about-mdeq/public-records-request/public-records-request-form/.  Additionally, a copy of the draft permit and statement of basis may be found on the MDEQ’s website at: https://opc.deq.state.ms.us/publicnotice.aspx. This information is also available for review at the office of the MDEQ at the Permit Board address shown above during normal business hours. Please bring the foregoing to the attention of persons whom you know will be interested.