South Carolina issues total stop order for Silfab Solar in Fort Mill after two chemical leaks

State regulators halt work as investigation expands after two releases in three days

South Carolina environmental regulators ordered Silfab Solar’s Fort Mill facility in York County to immediately cease all operations on Thursday, March 5, after a second chemical incident was reported at the site in the same week. The directive halted commissioning and other activity while state and federal regulators review the facility’s chemical safety controls and risk-management requirements.

The order followed two separate releases: a potassium hydroxide incident reported Tuesday, March 3, and a hydrofluoric acid incident reported Thursday morning. The facility sits near the Flint Hill school campus, a factor that has intensified scrutiny of emergency planning and chemical handling at the site.

What happened this week

• March 3: A release involving potassium hydroxide solution was reported during start-up activities. Initial figures circulated locally were later revised by the company, which stated the event involved no more than 300 gallons of water diluted to 0.03% potassium hydroxide. Local emergency management and hazardous materials personnel responded, and the incident triggered state action to pause chemical deliveries and start-up activities pending review.

• March 5: A second incident was reported involving hydrofluoric acid. County and company statements indicated the release was contained within controlled areas of the facility. Even so, the second event prompted the state to escalate its response from a delivery pause to a “cease all operations” directive.

What the stop order requires

The March 5 directive requires Silfab to place systems in a safe and secure condition and to provide confirmations and technical evaluations intended to prevent additional releases. Key requirements include:

• Stopping all operations, including commissioning activities, pending the completion of an investigation into the facility’s Risk Management Program by state regulators and the U.S. Environmental Protection Agency.

• Confirming there are no additional chemical leaks on site.

• Retaining a qualified professional engineer with expertise in chemical systems and equipment leaks, and providing evaluation results to regulators.

• Notifying regulators promptly of any future chemical release from piping or tank systems.

School impacts and public-safety actions

Following the March 5 incident, Flint Hill Elementary School closed Thursday, with district communications emphasizing precautionary steps and coordination with emergency management. The state attorney general issued a public-safety advisory the same day after the shutdown order, citing concerns tied to the facility’s proximity to schools and the back-to-back chemical incidents.

State regulators have ordered operations halted while investigations into chemical systems, reporting, and risk-management requirements proceed.

Background: a project under sustained local scrutiny

Silfab Solar, which has described its Fort Mill project as a major manufacturing investment with significant job creation, has faced sustained local debate over land use, permitting, and the appropriateness of chemical-intensive industrial operations near a school campus. The state’s March 5 action marks the most restrictive operational intervention to date and places the facility’s start-up timeline under regulatory control pending investigative findings and any required corrective measures.