Wacker chemical plant sees third incident in two weeks

Clouds billow from the Wacker polysilicon chemical plant after an explosion released a hydrogen chemical gas on Thursday, Sept. 7, 2017, in Charleston, Tenn. The explosion closed the plant, but a statement from Wacker says air quality was unaffected.

Alarms went off for the third time in two weeks at the Wacker Chemical Plant in Charleston, Tenn., on Tuesday, causing employees to again take shelter onsite.

A release from the company stated workers detected "a slight elevation of residual chemicals stemming from the September 7 incident."

"According to emergency protocol and precautionary measures, Wacker issued an onsite shelter in place, which has been lifted. There was no risk to the community or employees," the statement read.

"Safety is our top priority along with the care and well-being of our employees and our community. Our commitment to safety remains our primary focus."

A separate release from Bradley County Schools stated alarms were set off while work was being done on "damaged pipes with chemical residue."

"There