Aerial photo of Wacker Chemical site

Wacker Polysilicon has begun putting up the three largest buildings that will be constructed at its massive Bradley County plant.

"This first quarter of 2012 marks a milestone for our plant's construction," said Martin Richtberg, head of the $1.5 billion construction project near Charleston, Tenn.

He said the trio of buildings, the site's most complex, have precast walls which allow for the installment of a highly sophisticated system for producing hyperpure polysilicon.

"These first three buildings to be erected are integral to our closed-loop process and the production of polysilicon," Richtberg said.

More than 5,000 precast components will be used to build these facilities, with 1,800 installed to date. Over 30 buildings, which will either be precast structures or cast-and-place steel structures, are planned for the site.

Ground preparation for the site began in December 2010. The plant will open in late 2013 making polysilicon used in the solar industry.

On an average full day, there are about 700 construction workers on site.