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.

• Public Hearing Transcript

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:  

• Department Decision
• Permit
• Statement of Basis
• Response to Comments
• Letter to Citizens
• Air Permit Application (Revised 02-20-2024 and 02-22-2024)

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.

• Summary of the Silfab Synthetic Minor Air Quality Construction Permit

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.

• Silfab’s Update Modeling Forms
• BAQ Updated Modeling Summary

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

• Silfab’s Boiler Exemption Letter
• Silfab’s Submission for Exempt Boilers 

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.

• BAQ Acknowledgement Letter for Exempt Boilers and Updated Modeling
• BAQ Statement of Basis for Letter for Exempt Boilers

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.

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.

Facilities aren’t required to provide the names and locations of their chemical suppliers to SCDES. Silfab would have this information.

Silfab will be required to coordinate its emergency response plans with local emergency response agencies. That coordination is required prior to bringing regulated substances on-site and submitting its risk management plan (RMP) to the EPA. The RMP will provide information about possible impacts of a worst-case release scenario and also more realistic release scenarios. The local emergency response agencies will use this information to plan for their response. Silfab will be required to perform annual drills/exercises with these local response agencies. If a release has the potential to impact the schools or nearby residents, SCDES strongly encourages Silfab and the local emergency response agencies to include the schools and nursing home residents in these exercises. Decisions on signage, where to go and how long residents should be removed from homes, and when residents should return to homes will be made by the local emergency response agencies and the on-scene incident command on a caseby-case basis. SCDES only serves in an advisory capacity and will not be the lead agency for these decisions. Any possible home contamination claims would need to be addressed with Silfab.

The facility plans to store two regulated substances on-site: silane (a flammable gas) and hydrochloric acid (a toxic liquid). These chemicals are used at many facilities across the country and can be handled safely. Silfab is required to coordinate its emergency response plan with local emergency response agencies to determine the most appropriate procedures in the event an air release or a fire occurs at the site.

Silfab is required to coordinate its emergency response plan with the local emergency response agencies to determine the most appropriate procedures for any fire that may occurs at the site

Silfab is required to coordinate its emergency response plan with the local emergency response agencies to determine the most appropriate procedures and if any personal protective equipment (PPE) is necessary. It’s highly unlikely that PPE would be required outside of the fence-line of the facility.

Silfab is required to coordinate its emergency response plan with the local emergency response agencies to determine the most appropriate procedures for notifying schools, if necessary. Many decisions about these procedures will be made by local emergency response agencies on a case-by-case basis.

Wastewater from the facility will be pre-treated on-site and then discharged to the City of Rock Hill’s sewer system. The City of Rock Hill will be required to notify SCDES of the quality and quantity of the water being discharged to their system and any anticipated impact on the quantity or quality of water to be discharged from their system. SCDES regulates the City of Rock Hill’s discharges to ensure appropriate protections are in place for waters that may be a source of drinking water.

A traffic study was performed for this site by S.C. DOT, which could best answer this question.

Facilities are allowed to release some level of air pollution as long state and federal standards and air permit limits are met. These state and federal air quality standards are set to be protective of public health, especially children, the elderly, and those with respiratory conditions beyond the fence-line of a permitted facility. The air permit SCDES issued to Silfab in March 2024 has limits on the amount of air pollutants that can be released by the facility. It requires the air scrubbers to remove air toxic pollutants by at least 96%. The remaining emissions will be emitted through an exhaust stack. An air dispersion analysis was performed to simulate the dispersion of these air pollutants from the stack into the ambient air. This analysis showed the air emissions would not exceed any state or federal health-based standards that are protective of public health and the environment beyond the fence-line

Silfab demonstrated that its air emissions could meet all state and federal air quality standards. The federal standards were set to be protective of public health and the environment. There are no anticipated impacts to soil, wildlife or waters

If the scrubber system becomes inoperable, the process will automatically shut down. The air permit also requires Silfab to notify SCDES of any malfunction or upset that lasts more than one hour if emissions exceed the specified limits. It’s also required to minimize any excess emissions. The facility must monitor the operations of the air scrubber regularly and document readings to ensure it is operating properly in accordance with the manufacturer’s specifications. Records of this documentation will be periodically reviewed by SCDES inspectors.

SCDES isn’t involved with real estate issues.

The Occupational Safety and Health Administration (OSHA) requires chemical manufacturers to develop a safety data sheet (SDS) for each hazardous chemical they make or import. The SDS includes information about chemical uses and safety. The SDS is given to facilities that use these chemicals and the facility is required to maintain the SDS onsite. OSHA also requires that all employees be trained on how to safely handle all chemicals onsite. The facility is not required to retest the chemicals. 

Once the facility starts solar panel production, air emission stack testing will be required. The initial stack test for HCl and HF emissions will be required within 45 days of achieving the maximum production rate or within 180 days of starting operation, whichever comes first. This testing will be required every two years thereafter. Silfab will be required to hire a third-party testing company to perform the testing. SCDES staff will be on-site to ensure the test is done properly. 

In addition to stack testing, the facility will be required to monitor certain parameters daily in accordance with the conditions of its air permit to verify compliance with emission limitations and operational requirements. SCDES will perform unannounced inspections to assess operations, inspect the equipment and review monitoring records. The lowering of the stack height to meet county code (and the related appeal) do not impact the testing procedures or frequency.

SCDES doesn’t regulate the transport of chemicals. Silfab could provide this information.

SCDES regulates certain substances above certain quantities in tanks and containers. 

Silfab has proposed to store two 5,280-gallon tanks of hydrochloric acid (HCl), two 7,925-gallon tanks of hydrogen fluoride (HF) and one 22,983-gallon tank of silane. Silfab will also store diesel fuel on-stie to use in emergency generators. Other substances may be stored onsite in quantities that are not regulated. Not every chemical poses a risk to people or the environment. Pollutants are selected to be regulated based on whether and to what extent they can have negative effects on human health or the environment. 

Silfab will be required to submit a risk management plan (RMP) to the EPA that also will be shared with SCDES. This plan will outline how the facility plans to prevent accidental releases and its safety protocols. It will also show how the facility has coordinated its emergency response plan with local emergency response agencies. The facility is required to submit the RMP to EPA before it brings regulated substances on site. Silfab hasn’t submitted the RMP to EPA yet. Once submitted, SCDES will review it and schedule a compliance inspection. Once the facility is operating, experienced SCDES staff will conduct unannounced inspections. Contractors are not required and will not be used. The frequency of these inspections hasn’t been determined yet

Silfab will be required to coordinate its emergency response plans with local emergency response agencies. That coordination is required prior to bringing regulated substances onsite and submitting its risk management plan (RMP) to the EPA. The RMP will provide information about possible impacts of a worst-case release scenario and also more realistic release scenarios. These scenarios are generated using modeling software and population data. The local emergency response agencies will use this information to plan for a possible response, and Silfab will be required to perform annual drills/exercises with these local response agencies. If a release has the potential to impact the schools or nearby residents, SCDES strongly encourages Silfab and the local emergency response agencies to include the schools and nearby residents in these exercises.

Zoning and land use decisions are made by city or county zoning authorities. The interpretation, application, and enforcement of county zoning ordinances are outside of the Department’s purview.

The Department doesn’t have the authority to dictate where a facility may or may not be located or make zoning decisions. These zoning and land use decisions are made by city or county zoning authorities. The agency’s role is to ensure a facility operates in compliance with the environmental permits that are issued in order to protect people’s health and the environment.

Companies produce solar panels differently; no two facilities are identical. SCDES is aware of two existing facilities in operation in Georgia and two recently permitted facilities in South Carolina: 

• The existing facilities in Georgia are the Hanwha Q Cells USA facility in White and Suniva Inc., in Norcross.
• The two recently permitted facilities in South Carolina are Silfab Solar in Fort Mill and ES Foundry in Greenwood. 

The Greenwood facility is very similar to Silfab and will also use silane, hydrochloric acid (HCl) and hydrogen fluoride (HF) and will have similar air emissions. It's our understanding that the zoning for the Greenwood facility is Light Industrial, however, zoning definitions vary by municipality. 

The Georgia facilities use chemicals similar to the chemicals Silfab and ES Foundry plan to use but in smaller quantities. 

Of note, the semiconductor industry uses the same types of chemicals and has similar processes and emissions as the solar panel industry. SCDES is aware of at least two semiconductor facilities in the country, in Midland, Mich., and Austin, Texas.

After the facility begins operations, air emission stack testing will be required. The initial stack test for HCl and HF emissions will be required within 45 days of achieving the maximum production rate or within 180 days of starting operation, whichever comes first. This testing will be required every two years thereafter. Silfab will be required to hire a third-party testing company to perform the testing. SCDES staff will be on-site to ensure the test is done properly. 

In addition to stack testing, the facility will be required to monitor certain parameters daily in accordance with the conditions of its air permit to verify compliance with emission limitations and operational requirements. SCDES will perform unannounced inspections to assess operations, inspect the equipment and review monitoring records.

Silfab is the first solar panel production facility to receive an air permit in South Carolina. A second solar panel production facility has received an air permit in Greenwood. More than 2,000 facilities in South Carolina have air permits issued by SCDES (or the former DHEC). Experienced SCDES permitting engineers and inspectors, with various expertise, perform their duties with respect to these 2000+ facilities across South Carolina. There are no specific credentials required for permitting and inspecting solar panel facilities.

Silfab will use a wet acid scrubber system to control air toxic emissions. More than 50 facilities across South Carolina use scrubbers to control air emissions every day. Many of these facilities are required to test their scrubbers and have shown compliance with their air permit limits on a regular basis. Scrubber parameters, including pressure drop, liquid flow rate, and pH, will be monitored and recorded daily by Silfab staff to ensure the scrubber system is operating effectively. Also, if the scrubber system becomes inoperable, the process will automatically shut down.

Silfab will be required to coordinate its emergency response plans with local emergency response agencies. That coordination is required prior to bringing regulated substances onsite and submitting its risk management plan (RMP) to the EPA. Local emergency response agencies will use this information to plan for their response, and those agencies will determine the number of people needed to assist with any emergency. Public copies of risk management plans can be found at https://cdxapps.epa.gov/olem-rmppds/ once they are submitted. Please note that some portions of risk management plans are considered sensitive by state and federal law and will not be available on the public website. Appointments to see the full RMP and this sensitive information must be made in accordance with SC law found at https://dph.sc.gov/sites/scdph/files/Library/Regulations/R.61-117.pdf or by visiting a federal reading room. More information about federal reading room appointments can be found at https://www.epa.gov/rmp/federal-reading-rooms-risk-management-plansrmp#make%20appointment.

Silfab will be required to coordinate its emergency response plans with local emergency response agencies. No outside third-party tests are required. Silfab will be required to perform annual drills/exercises with these local response agencies. Please see the information above about obtaining access to RMP information.

The risk management plan (RMP) will provide information about possible impacts of a worstcase release scenario and also more realistic release scenarios. Please see the information above about obtaining access to RMP information.

Due to agency-wide technology changes that took place during the weekend of Sept. 6-9 that temporarily limited some website capabilities, SCDES extended the time frame to submit questions to Sept. 13, 2024. We apologize for this inconvenience. The link for submitting questions was active from Aug. 27-Sept. 7, was impacted by website technology changes Sept. 8-9, and was active again from Sept. 10-15.

Silfab has not submitted their RMP and worst-case scenario analysis yet. Public copies of risk management plans can be found at https://cdxapps.epa.gov/olem-rmp-pds/ once they are submitted. Please note that some portions of risk management plans are considered sensitive by state and federal law and will not be available on the public website. Appointments to see the full RMP with this sensitive information can be made in accordance with South Carolina state law found at https://dph.sc.gov/sites/scdph/files/Library/Regulations/R.61-117.pdf or by visiting a federal reading room. More information about federal reading room appointments can be found at https://www.epa.gov/rmp/federal-reading-rooms-risk-management-plansrmp#make%20appointment.

If not, can the state perform a worst-case scenario analysisto determine if the schools can be impacted?

Please see the information above about how to access the RMP.

No. The facility in Washington State only assembles solar panels. The chemicals used at the Washington site are for cleaning and soldering the panels. These chemicals are not the same as those proposed for the Fort Mill site.

Companies produce solar panels differently; no two facilities are identical. SCDES is aware of two existing facilities in operation in Georgia and two recently permitted facilities in South Carolina: 

• The existing facilities in Georgia are the Hanwha Q Cells USA facility in White and Suniva Inc., in Norcross.
• The two recently permitting facilities in South Carolina are Silfab Solar in Fort Mill and ES Foundry in Greenwood. 

The Greenwood facility is very similar to Silfab and will also use silane, hydrochloric acid (HCl) and hydrogen fluoride (HF) and will have similar air emissions. It's our understanding that the zoning for the Greenwood facility is Light Industrial, however, zoning definitions vary by municipality. 

The Georgia facilities use chemicals similar to the chemicals Silfab and ES Foundry plan to use but in smaller quantities. 

Of note, the semiconductor industry uses the same types of chemicals and has similar processes and emissions as the solar panel industry. SCDES is aware of at least two semiconductor facilities in the country, in Midland, Mich., and Austin, Texas.

SCDOT performed a traffic study for this site and is the best agency to answer this question.

The initial stack test for hydrochloric acid (HCl) and hydrogen fluoride (HF) emissions will be required within 45 days of achieving the maximum production rate or within 180 days of starting solar production operation, whichever comes first. This testing will be required every two years thereafter. Silfab will be required to hire a third-party testing company to perform the testing. SCDES staff will be on-site to ensure the test is done properly. 

In addition to stack testing, the facility will be required to monitor certain parameters daily in accordance with the conditions of its air permit to verify compliance with emission limitations and operational requirements. SCDES will perform unannounced inspections to assess operations, inspect the equipment and review monitoring records.

First, SCDES will review the stack test data and report to determine compliance with the air permit. Any potential violations would result in the facility being referred to the enforcement section of the agency’s Bureau of Air Quality. If the enforcement section confirms that a violation has occurred, enforcement

No air permit from SCDES is required for the warehousing and distribution of solar panels.

SCDES was aware Silfab would be using an existing warehouse to produce solar panels and that this warehouse is located in an area that is zoned by the county as Light Industrial District (LI). Zoning and land use decisions are made by city or county zoning authorities. The interpretation, application, and enforcement of county zoning ordinances are outside of the Department’s purview. The agency’s role is to ensure a facility operates in compliance with the environmental permits that are issued in order to protect people’s health and the environment.

SCDES was aware Silfab would be using an existing warehouse located in an area that is zoned by the county as Light Industrial District (LI). Zoning and land use decisions are made by city or county zoning authorities. The interpretation, application, and enforcement of county zoning ordinances are outside of the Department’s purview. The agency’s role is to ensure a facility operates in compliance with the environmental permits that are issued in order to protect people’s health and the environment.

Zoning and land use decisions are made by city or county zoning authorities. The interpretation, application, and enforcement of county zoning ordinances are outside of the Department’s purview. The agency’s role is to ensure a facility operates in compliance with the environmental permits that are issued in order to protect people’s health and the environment.

Not all chemicals are regulated pollutants. There may be some chemicals stored onsite that are exempt from permitting or may not be regulated by state or federal regulations. All regulated air pollutants, including air toxics, were evaluated and addressed in the air permit. The county conducted the technical review for the stormwater runoff permits for the site. If the facility generates any hazardous waste after it starts operation, it will be required to comply with state and federal hazardous waste generator laws.

Silane is not a regulated air pollutant and not an air toxic. It is regulated as a flammable gas under the risk management program. 

There are many facilities in South Carolina and across the country that report emitting toluene, hydrogen fluoride, VOCs and hydrochloric acid emissions annually. In South Carolina, at least 260 facilities report emitting at least one of these pollutants; at least 150 emit two of these pollutants; at least 60 facilities facility emit three of these pollutants; and at least 20 facilities emit all four of these pollutants. Requests for this list can be obtained by contacting our Freedom of Information office. 

Please note SCDES does not have zoning information for these locations, as zoning requirements vary by municipality. Some areas have no zoning laws at all. 

All facilities that are required to obtain an air permit are required to do an air quality analysis. The air quality analysis performed for Silfab demonstrated that the facility would not exceed any state or federal health-based standards that are protective of public health and the environment beyond the fence line.

Only regulated air pollutants and regulated substances under the risk management program are required to be listed in the air permit application. Some chemicals may be stored or used onsite in quantities below regulated thresholds or exemption level and, therefore, do not need to be included in the air permit.

There is no Dow Company facility currently operating in South Carolina. We are not aware of the chemicals this company does or does not use.

SCDES is aware of the ongoing U.S. Chemical Safety Board’s investigation of the 2023 release of HF from the Honeywell facility in Louisiana. 

The storage amounts of silane, HCl, and HF and the air emissions information for three air toxics (HCl, toluene, and HF) were included in Silfab’s air permit application. This information was reviewed and evaluated by SCDES. 

The air permit establishes limits on air emissions based on the air quality analysis performed. The air quality analysis also demonstrated that the facility would not exceed any state or federal health-based standards that are protective of public health and the environment beyond the fence line. 

The facility will be required to comply with the risk management program for silane and hydrochloric acid prior to bringing those substances onsite. Silfab is not subject to the risk management program for hydrogen fluoride because the concentration will be less the 50%.

Prior to bringing the silane and hydrochloric acid on site, the facility will be required to comply with the risk management program and submit a risk management plan to the U.S. EPA. This plan will show the impacts of possible accidental releases. The facility has not submitted its risk management plan yet. Once the risk management plan is submitted, SCDES staff will review the plan and conduct a compliance inspection. Public copies of risk management plans can be found at https://cdxapps.epa.gov/olem-rmp-pds/ once they are submitted. Please note that some portions of risk management plans are considered sensitive by state and federal law and will not be available on the public website. Appointments to see the full risk management plan and this sensitive information must be made in accordance with South Carolina state law available at https://dph.sc.gov/sites/scdph/files/Library/Regulations/R.61-117.pdf or by visiting a federal reading room. More information about federal reading room appointments can be found at: https://www.epa.gov/rmp/federal-reading-rooms-risk-management-plansrmp#make%20appointment.

When a facility submits an air permit application, they are required to assume 24/7 operations to determine the worst-case air emissions, even if the facility does not plan to operate that many hours. If the facility can demonstrate it can meet all state and federal air quality standards operating 24/7, there are no restrictions on hours of operation listed in the air permit. Most facilities that operate 24/7 do shutdown for periods of time to perform routine maintenance.

The Department does not have the authority to dictate where a facility may or may not be located or make zoning decisions. These zoning and land use decisions are made by city or county zoning authorities. The agency’s role is to ensure a facility operates in compliance with the environmental permits that are issued in order to protect people’s health and the environment. 

An air quality analysis was performed for the three air toxic pollutants, and the analysis demonstrated that the facility would not exceed any state or federal health-based standards that are protective of public health and the environment beyond the fence line.

The air quality analysis submitted with the permit application considered offsite public receptors (such as schools, businesses, and parks) and demonstrated that the facility would not exceed any state or federal health-based standards that are protective of public health and the environment beyond the fence line.

The air quality analysis submitted with the permit application included the location of the 2 new schools and demonstrated that the facility would not exceed any state or federal healthbased standards that are protective of public health and the environment beyond the fence line.

It is standard permitting practice across the country for the monitoring, testing, recordkeeping, and reporting requirements of an air permit to be the responsibility of the facility. The facility may perform the requirements of the permit itself or outsource it to a contractor. SCDES will review all compliance information submitted by the facility (and obtained onsite during unannounced inspections) to determine compliance with the air permit.

Silfab will be required to coordinate its emergency response plans with local emergency response agencies, and that coordination is required prior to bringing regulated substances onsite and submitting its risk management plan (RMP) to the EPA. The RMP will provide information about possible impacts of a worst-case release scenario and also more realistic release scenarios. The local emergency response agencies will use this information to plan for a possible response. Notifications to the public will be made by the local emergency response agencies and the on-scene incident command as needed. 

Facilities are also required to report leaks or releases that exceed a reportable quantity (RQ) that leave the plant property promptly to the EPA National Response Center (NRC) and SCDES. Reportable quantity (RQ) thresholds can be found at https://www.epa.gov/epcra/consolidatedlist-lists. Reports sent to the NRC are available to the public and can be found at: https://www.epa.gov/emergency-response/national-response-center. If a leak or release is below the RQ and does not go offsite, no notification is required.

The disposal of wastes and landfills are regulated by SCDES’s land and waste program. If the facility generates any hazardous wastes after it starts operation, it will be required to notify SCDES and comply with the state and federal hazardous waste generator laws.

When a facility submits an air permit application, they are required to assume 24/7 operations to determine the worst-case air emissions, even if the facility does not plan to operate that many hours. The air quality analysis submitted with the permit application considered offsite public receptors (such as schools, businesses, and parks) and demonstrated that the facility would not exceed any state or federal health-based standards that are protective of public health and the environment beyond the fence line.

EPA Region 4’s Senior Toxicologist provided the following responsse:

“EPA notes that there is not presently a source standard for solar panel manufacturing pursuant to Clean Air Act section 112. This facility will be a synthetic minor facility for HAPs, meaning emissions will be restricted below “major source” thresholds of 10 tons per year of individual HAPs, or 25 tons per year of combined HAPs, so there is also no requirement for a case-by-case maximum achievable control technology determination. This means there is no federal requirement to continuously monitor emissions of HCl or HF at the facility. 

However, Condition B.1 of the air permit limits overall annual HAP emissions from the facility, and Condition B.6 requires a specific efficiency of wet scrubbers intended to control the emissions of these pollutants. Condition B.6 requires initial and ongoing testing of these scrubbers, which will establish the operational ranges required to be established in Condition B.7. Condition B.8 then requires that several parameters indicating the adequate operation of the scrubbers must be measured and recorded daily. The permit further states at Condition B.8 that “Each scrubber shall be in place and operational whenever processes controlled by it are running.” This means that the manufacturing process is required to be controlled to this degree at all times. Conditions B.4 and B.8 require that any deviations from established operational ranges are reported along with any corrective actions at least semiannually, which is consistent with reporting requirements for major sources and other stationary source programs. Should there be downtime for the wet scrubbers, the process should be halted. Permit Condition B.1 requires emissions from malfunctions to be included in determining compliance with the annual emission limits, and as noted above, any deviations from normal operating parameters are recorded and reported. Further, Condition F.5 contains a reporting requirement within 24 hours after the beginning of the malfunction of air pollution control equipment for any discharges lasting for one hour or more. The State will therefore have the information necessary to determine compliance with the permit conditions. 

Should there be accidental releases from the storage of these chemicals, that occurrence would not be considered part of normal operation, so the State’s risk management plan regulations establish requirements to address this scenario. Specifically, the permit requires the submission of a risk management plan for HCl and for silane. This plan is used to inform local emergency response agencies. 

The State’s initial response to comments document, along with the newer “Q and A” document at the website identified previously, address some of these issues in greater detail. Please continue to follow up with South Carolina Department of Environmental Services’ Air Permitting Division with specific concerns.”

An environmental impact study (EIS) is a tool that is used for identifying and analyzing specific activities that are determined to likely have a significant adverse environmental impact. They are performed by federal government agencies and are only required by federal law for some projects that use federal land, federal tax dollars, or are under federal agency jurisdiction. An EIS was not required for this site. However, a state air quality construction permit was required. SCDES performed a thorough technical review of the air permit application and provided the public opportunities to provide input prior to the issuance of the air permit. More information about the technical review and public participation process can be found at Silfab Solar | South Carolina Department of Environmental Services.

Silfab’s air permit was issued on March 1, 2024. A copy can be found at AIR-ConstructionPermit-CP-50000090.pdf. This air permit outlines all the recordkeeping, reporting, testing, and monitoring requirements to meet state and federal air quality standards. SCDES staff enforce these requirements by conducting unannounced compliance inspections and complaint investigations, reviewing periodic compliance reports and onsite inspection logs, observing stack tests performed by a third-party, and taking enforcement action when violations are found.

The monitoring and testing requirements are outlined in the air permit. More details about the monitoring and testing requirements can be found in the Response to Comments Document at Silfab-Solar-Response-to-Comments-on-Air-Quality-Draft-Permit.pdf starting on page 4.

Any potential air permit violation would result in the facility being referred to the agency’s Air Compliance Management Division within the Bureau of Air Quality. If the agency confirms that a violation occurred, we will require any necessary corrective actions and may impose civil penalties.

The facility must correct a violation within a reasonable timeframe. SCDES will pursue necessary enforcement or other action to address any ongoing noncompliance.