Silfab Solar Community Forum and Residents' Follow-up Questions

Congressman Ralph Norman held a Community Forum about the proposed Silfab Solar manufacturing facility on Tuesday, Aug. 27. Rhonda Thompson, Bureau of Air Quality Chief, provided a presentation on the Air Quality permitting process.  

While SCDES has issued the environmental permits outlined below and provided a 23-page response to public comments as part of its permitting process, during the Aug. 27 community forum, residents asked to receive additional answers to questions they had about the Silfab facility. This Q&A document provides responses to those questions that are within the agency's authority to answer. 

We'll continue to make updates to this webpage as there is new information to provide as part of our ongoing efforts to keep residents informed about SCDES's oversight of regulated facilities in South Carolina to protect the health and wellbeing of people and the environment.


Air Quality Synthetic Minor Construction Permit

On June 5, 2023, the Bureau of Air Quality (BAQ) received a construction permit application from Silfab Solar (Silfab) to construct and operate a solar cell and panel production facility in Fort Mill.

The project included the following process areas:

  • Three Module Assembly Lines
  • Module Assembly Lab and Gel Content Testing
  • Phase 1 and Phase 2 Cell Manufacturing
  • Two Hydrofluoric Acid Storage Tanks
  • Two Hydrochloric Acid Storage Tanks
  • One Emergency Generator
  • Silane International Organization for Standardization (ISO) Module Multiple Element Gas Container (MEGC)
  • Direct Fired Thermal Oxidizer

The project included the following air pollution control devices:

  • Two Wet Acid Scrubbers 
  • One Venturi Scrubber

Once the technical review of the application was completed, a draft synthetic minor construction permit, draft statement of basis, and permit application were placed on public notice from August 9 – September 7, 2023. The technical review included reviewing emissions calculations, performing a regulatory review, conducting an ambient air quality analysis, and verifying the proposed project can meet all applicable air quality regulations if constructed and operated in accordance with the air permit and associated permit application.

During the public comment period, BAQ received more than 400 written and oral comments, including a request for a public hearing. The public hearing was held on October 30, 2023, and the public comment period was extended through November 3, 2023.

Department staff reviewed and considered each public comment received. As a result of this process, some air permit conditions were changed or added based on public comments received.

The Department issued the permit to Silfab on March 1, 2024, after determining that Silfab had demonstrated it can meet applicable air quality regulatory standards and requirements, which are designed to protect public health and the environment, by complying with the conditions of the permit.  This permit decision was made after a careful and extensive review of the following: the permit application and associated revisions, applicable state and federal air quality regulations, comments made at the public hearing, and all comments received within the public comment period. On March 1, the same day the permit was issued, a copy of the permit and a response to public comments were emailed to everyone who signed up to receive updates about this permit application.

The Department Decision, the construction permit, statement of basis, response to comments, and the letter to the citizens are available below:  

The permit authorizes the construction and operation of module manufacturing equipment and processes, solar cell manufacturing equipment and processes, a diesel-fired emergency generator, and chemical storage tanks (two 5,280-gallon storage tanks for storing 37% hydrochloric acid; two 7,925-gallon storage tanks for storing 49% hydrogen fluoride; and two tube trailers for holding 26,456 lbs of silane).

The air permit includes requirements for stack testing, monitoring, record-keeping, reporting, and emergency response planning coordination with the local fire department. The South Carolina Department of Environmental Services (SCDES) will conduct unannounced compliance inspections at the facility and will respond to any complaints or concerns reported by the public. In addition, as part of its risk management program, the facility is required to conduct an off-site consequences analysis identifying possible hazards and potential impacts, train all employees on the hazards of chemicals stored on-site, and ensure each employee working directly with a regulated substance receives training in operating procedures. The facility also must develop an accident prevention and emergency response plan that addresses the unique characteristics of its property and chemicals, coordinate its plan with response agencies (e.g., local fire department), and develop procedures for informing the public and response agencies should an accident occur. The Department reviews all compliance information submitted by permitted facilities or obtained on site and responds to any noncompliance through enforcement action as needed.

On June 4, 2024, Silfab informed the BAQ that it would be modifying the proposed stack heights for the facility to meet county requirements. The facility was directed to submit an air dispersion modeling analysis to verify a changed stack height would meet all state and federal air quality standards. The modeling has been submitted for the updated stack height. The new modeling analysis has been reviewed, and it demonstrates that the facility can meet all state and federal ambient air quality standards at the proposed updated stack height; therefore, no air permit modifications are needed at this time.

On June 25, 2024, Silfab submitted a written notification of its intent to install four small boilers which are exempt from construction permitting.

On July 30, 2024, the BAQ responded to Silfab’s notification regarding the exempt boilers and updated modeling. BAQ acknowledged the permitting exemption and verified that the updated modeling analysis demonstrated continued compliance with the modeling standards. No additional construction permitting or permit revision is required.

Stormwater Permit

York County operates and maintains a Municipal Separate Storm Sewer System (MS4) program for un-incorporated area of the county. They are required to develop and implements a local stormwater management program, including a mandate to develop ordinances, policies, and procedures to review stormwater management and sediment/erosion control plans for land disturbance within the county. County staff conduct a technical review of sediment/erosion control plans for compliance with local ordinances and state stormwater regulations. Upon county approval, once the application package is reviewed and approved by York County, a notice is sent to SCDES to perform an administrative review and grant coverage under the NPDES General Permit for Stormwater Discharges from Construction Activity.

The building Silfab plans to utilize for operations was permitted in 2020, prior to the company being involved with this site.  York County reviewed and approved the stormwater management and sediment/erosion control plans for the land disturbance and the former DHEC (now SCDES) issued the permit coverage in 2020 with a modification in 2021.

More recently, the Department received approval of land disturbance activities and notice from York County on April 24, 2024, requesting to disturb an additional one acre for parking, utility modifications, and landscaping at 7149 Logistics Lane (the proposed site for the Silfab manufacturing facility). The Department granted permit coverage on May 14, 2024.

Wastewater Pretreatment System Construction Permit

This permit was issued on May 24, 2024, for the installation of a pretreatment system, as Silfab will be a significant industrial user and will discharge to the sanitary sewer system of Rock Hill.

The system is required to have an operator who has been certified by the Environmental Certification Board of the South Carolina Department of Labor, Licensing and Regulation.

Silfab must develop, implement, and maintain a Best Management Practice (BMP) Plan to identify and control the discharge of significant amounts of oils and the hazardous and toxic substances. The plan must include a listing of all potential sources of spills or leaks of these materials, a method of containment, a description of training, inspection and security procedures, and emergency response measures to be taken in the event of a discharge to surface waters or plans and/or procedures which constitute an equivalent BMP.

Once construction of the pretreatment system is complete, Silfab must send a letter from a registered engineer certifying that the construction has been completed in accordance with the approved plans and specifications. However, the approval will not be granted, and the system cannot be placed into operation, until a final industrial discharge permit is issued by City of Rock Hill.