Wacker Chemie says that their investigation into the "root-cause" of the September 7 explosion at the Charleston plant is "well underway."

The investigation, being conducted by an unnamed "an independent expert team" is cooperating with governmental authorities, according to a Wacker news release.

The explosion was caused by a technical defect prompting a leak of hydrogen which subsequently caught fire, severely damaging a small facility at the production plant. The chemical release of hydrogen chloride (hydrochloric acid) and the resulting plume of vapor was seen for miles.

Twelve people were hurt in the explosion that forced neighbors of the plant to shelter in place and closed Interstate 75 for several hours. Wacker issued a public apology to the neighboring community in a full-page newspaper advertisement

Wacker says production at the plant will be suspended for several months until "a thorough inspection is completed and it is certain that the facility is safe.”

That process is expected to take several months, according to Tobias Brandis, Global President at Wacker Polysilicon.

Employees will be utilized to perform repairs and take advanced training courses.

The financial effects to Wacker are expected to be minimal due to insurance coverage for damages and loss of production.

Wacker's press release is below in its entirety: