Chemical release – repeated leaks (KOH and HF)

Incident Descriptions

A potassium hydroxide (KOH) solution was released at the Silfab Solar facility.
The release exceeded secondary containment and reached a nearby stormwater retention pond.
South Carolina Department of Environmental Services (SCDES) dispatched officials to the site and, the same day, advised Silfab to pause start‑up and refrain from receiving additional chemicals pending investigation.

A second incident involved a hydrofluoric acid (HF) leak from a tank system at the facility.
SCDES’s letter notes that the HF leak was fully contained and monitored within the building.
The leak had first been noticed as a “small drip” at the base of the tank during offloading; a vendor’s recommendation to tighten a flange reduced the leak rate to about one drip per hour, reportedly below normal reporting thresholds.

After the second leak, SCDES formally recommended that Silfab:
- Immediately halt all operations, including commissioning, until SCDES and the U.S. Environmental Protection Agency (EPA) complete investigations.
- Confirm that there are no other leaks onsite.
- Provide an evaluation by a qualified professional engineer with expertise in chemical systems and equipment leaks.
- Notify SCDES promptly of any future leaks from piping or tank systems.
Silfab agreed on Thursday evening to pause operations, and SCDES indicated it will pursue legal action if the facility resumes operation before investigations are complete.
The second leak led to the closure of a local elementary school on Thursday and Friday as a precaution, according to local news (Queen City News).

Silfab’s director of operations stated that the first incident involved approximately 300 gallons of water containing “small amounts” of potassium hydroxide.
The hydrofluoric acid leak was described as a very small drip rate after flange tightening, though it still triggered regulatory concern given HF’s toxicity and the plant’s recent leak history.

This pair of incidents highlights several critical chemical‑management and process‑safety points for high‑tech manufacturing sites:

Containment and secondary containment: Even “dilute” chemical solutions can present environmental risk when they escape primary containment and reach stormwater systems or surface waters; robust bunds, leak detection, and isolation valves are essential.
Tank and piping integrity: HF and KOH service require high‑reliability tanks, flanges, gaskets, and offloading systems, with strict procedures for connection, inspection, and verification before and during transfers.
Management of small, chronic leaks: “Drips” from critical chemical systems must be treated as leading indicators of failure; repairs should follow formal management‑of‑change and engineering review, not only vendor advice at site level.
Regulatory coordination and transparency: Prompt notification, cooperation with environmental authorities (SCDES, EPA), and transparent communication with affected communities (e.g., schools) are essential to maintain trust and protect public health.
Operational pause after repeated events: Multiple leaks within days justify temporary shutdown, full system review, and independent engineering assessment before restart.