After converting an abandoned manufacturing plant originally built for solar-panel manufacturer First Solar Inc., Apple Inc. has started shipping sapphire glass from its new production site in Mesa, Ariz. The facility's revival and ongoing construction continue after months of political maneuvering, the price collapse of solar panels and the subsequent fire sale to save the multimillion-dollar development.

Apple is unwilling to disclose much about the plant's output, but technology blogs and analysts say the firm is working with GT Advanced Technologies, New Hampshire, to develop a thinner, more scratch-resistant alternative to Corning's Gorilla Glass for the next generation of iPhone screens.

Apple says the Mesa project will create 1,300 construction jobs. The United Association of Plumbers and Pipefitters 469, Phoenix, says the fast-track job means work for 200 or more of its members for the rest of 2014. Work includes "installation of condenser water systems, chiller water systems and inert-gas systems [entailing] the use of 48-inch pipes down to six-inch pipes," said a union spokesman.

"They started back in November and have been working two shifts, seven days per week," says Roy Hamilton, business manager for the International Brotherhood of Electrical Workers 640. "We had about 400 members out there, but most of the work is finishing up now. The furnaces that melt the silicone and turn it into the sapphire glass need an enormous amount of electrical power, much more than the solar-panel process needs." He adds, "SRP had to build two new switchyards for this project—that's how much power it's going to use."

After First Solar departed, state officials and developers scrambled to find a buyer for the plant. Senate Bill 1413, which passed in February, eliminates an electricity sales tax for manufacturers and mining smelters.

Another state bill, SB 1484, provides a $5-million tax credit if Apple installs at least $300 million in renewable-power capacity to supply the Mesa plant. Gov. Jan Brewer (R) signed both measures into law in April.

In addition, the Mesa site was declared a free-trade zone, so goods can be shipped and received internationally without oversight from customs agents.

Apple owns the Mesa site but will be leasing it to GT Advanced, which owns particle-acceleration technology that can very thinly slice hard materials. It can cut sapphire into thin sheets at a fraction of the cost of traditional methods, the company says. The process originally was developed for making film for solar panels. First Solar says the plant has the largest solar rooftop in the world.

In its first-quarter review of GT Advanced, UBS Research, New York City, reported that hundreds of sapphire furnaces, which grow crystals and produce high-grade material, already are installed at the site, and the first shipments are now going to customers in China. UBS said that, in total, nearly 1,200 furnaces will be up and running this year.

UBS also said GT Advanced confirmed payments from Apple that indicate construction is on schedule at the site.