Silfab Solar plans to resume commissioning chemical and gas systems at its Fort Mill solar cell plant no sooner than mid October, the company said Wednesday as it released an independent engineering review that found its safety measures in line with industry standards but flagged gaps in gas monitoring, design records and emergency communications.
The documents, which Silfab provided to the Tega Cay Sun on Sept. 30, answer requirements in the company’s March 16 compliance agreement with the South Carolina Department of Environmental Services following a March 3 spill at the plant at 7149 Logistics Lane. They include the report from TRC Engineers Inc., Silfab’s response, an unredacted analysis of the spill and a letter from President and CEO Paolo Maccario.
What the engineers found
Silfab hired TRC, which reviewed the plant from April through August. The firm credited double wall piping, storage rooms built to hold a full tank and about 26 toxic gas monitors, and concluded that Silfab’s measures were “consistent with industry standards for handling the chemicals of interest.”
Because commissioning was paused, TRC could not see equipment running or test alarms, and the report states it provides no certification or guarantee.
TRC’s code review marked five areas where the design did not meet code or documentation was missing, including the lack of gas monitors in exhaust ducts from the silane and ammonia enclosures and an ammonia relief valve that vented beneath a canopy. The firm also found no containment around the scrubber and no method to control vapors that would escape through a roof vent if acid spilled in the hydrofluoric and hydrochloric acid storage room.
TRC observed a June 3 evacuation over a propane incident. The plant’s intercom was not fully installed, and managers relied on Microsoft Teams messages and verbal instructions instead.
Fort Mill School District officials told TRC that parents call schools each time an emergency vehicle goes to the plant and that Silfab’s notifications to the district had dropped off in recent months.
Silfab’s response
In a response signed by Director of Operations Greg Basden, Silfab agreed with all 20 of TRC’s recommendations and reported eight closed, including the new gas monitors, an opening of about 18 feet by 50 feet cut into the ammonia canopy and a working intercom. Remaining items carry October target dates.
Of 23 additional best practices TRC suggested, Silfab said 15 are complete and six remain under review, among them a formal hazard study for which “timing is not confirmed” and added ventilation for the acid storage room. Silfab said it will notify Fort Mill Schools of any Level 3 incident, its most serious category.
The March spill
Silfab’s April 13 analysis traces the March 3 spill to a water valve on the scrubber that likely failed in freezing weather. An operator filling the unit by hand overfilled it, and about 300 gallons of water containing 0.5 percent potassium hydroxide escaped through a broken drain line into the stormwater pond on the property. Silfab said the water did not leave the site and the pond was emptied at York County’s request.
What comes next
Maccario wrote that TRC confirmed the plant’s safety systems “meet or exceed regulatory standards.”
Silfab must give DES 72 hours’ notice before receiving chemicals or restarting commissioning. The media statement puts the earliest date at Oct. 18, while the schedule filed with DES says Oct. 19. Silfab’s appeal of a circuit court ruling that solar cell manufacturing is not permitted under the site’s zoning remains pending.
The full report and related documents are available below
Silfab_DES report_ Management Commitment
GBB_Silfab Response to TRC Report
GBB_Silfab Scrubber Incident Report
Silfab Media Statement for TRC report
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Thomas Hyslip lives in Tega Cay with his wife and daughter. After 27 years in the U.S. Army and Federal Law Enforcement, he retired to pursue his passion for teaching. Tom is now an Assistant Professor of Instruction at the University of South Florida. In 2 short years he has won 10 awards from the South Carolina Press Association, including first place in column writing, education beat reporting and best podcast.
