Staff file photo / The Wacker production plant in Bradley County manufactures polysilicon for use in solar power panels.

This story was updated on Tuesday, April 27, 2021, at 5:13 p.m. with additional information.

Wacker's Bradley County plant, the site of a fatal incident last year in which one person died and four others were injured, has been cited for a "serious violation" and fined, according to state documents.

The polysilicon maker received a proposed fine of $3,200 for the Nov. 13, 2020, incident from the Tennessee Department of Labor and Workforce Development's Division of Occupational Safety and Health, or TOSHA.

The TOSHA report said that types of personal protective equipment were not selected to protect the affected Pen Gulf Inc. employees from the hazards identified during an assessment for a Jake Marshal LLC safe-work permit.

The fatal mishap took place during maintenance activity at the sprawling Bradley County factory that makes polysilicon for use in solar panels, according to the Tennessee Department of Environment and Conservation.

The incident resulted in a release of about 15 pounds of hydrochloric acid (HCl), a TDEC statement said.

Wacker spokeswoman Lisa Mantooth said the company won't appeal the TOSHA findings.

She said Wacker fully cooperated with TOSHA's investigation and will implement all of the corrective measures required by the agency. Wacker also is working with safety consultants to identify and implement additional steps to improve worker safety at the plant, Mantooth said.

"In addition to the consultants, Wacker will utilize all available resources, including its global network and its 100-plus years of experience, to ensure that the Charleston, Tennessee, site is fully safe for all personnel, contractors, visitors and the surrounding community," she said.

In 2016, the German company opened the $2.5 billion Bradley County plant, the biggest ever single manufacturing investment in Southeast Tennessee. Later, another $150 million was invested to turn a byproduct of its polysilicon factory into pyrogenic silica, a viscosity-adjusting agent in coatings, printing inks and adhesives. Then, officials planned to hire another 50 workers to join the 650 already employed there.

But the Wacker plant has experienced several chemical releases or worker injuries since it opened, though last November's was the first to involve a death.

In July 2020, four contract workers at the plant were injured while performing maintenance in one of the process buildings at the facility.

That incident came less than three years after a chemical explosion at the Wacker plant in September 2017 injured 13 people, including plant workers, a firefighter and nearby residents. Wacker determined that a piston failure ignited a plant fire and sent 1,784 pounds of hydrochloric acid into the air.

TDEC concluded that explosion was caused by a "sudden and unavoidable failure of process equipment."

"Because the event meets the definition of a malfunction, and it is unlikely that public health or the environment were impacted due to the excess [hydrochloric acid] and [trichlorosilane] emissions, it is recommended that no enforcement action be taken for the excess emissions resulting from the event," a report said about that incident.

A TOSHA investigation into the same incident determined there were five serious violations and two "other-than-serious" violations that resulted in more than $25,000 in fines. A separate TOSHA investigation into an unrelated chemical spill that sent five workers to area hospitals a week prior to the explosion found two serious violations resulting in more than $20,000 in fines.

Wacker officials suspended chemical production for nearly eight months following the explosion as they looked into the incident, hired a third-party investigator, cleared the area of dangerous debris and chemicals, and made safety improvements to the facility.

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