So here's something to consider: The new World Trade Center (WTC) currently under construction in New York City is using Chinese-made glass windows for its first 20 stories.

Even though three U.S. glass manufacturers, including Pittsburgh-headquartered PPG Industries, spent months working with WTC tower architects to plan and develop a new kind of glass for the project, none of these American companies was awarded the contract.

Instead, as the Washington Post reported, a Chinese firm received the job after it underbid its U.S. competitors.

Here's something else to consider: Since 2004, China’s glass manufacturers have received at least $30 billion in government subsidies. These subsidies violate world trade law and have helped to distort the global market, but they offer some explanation for why a Chinese firm was able to underbid its U.S. rivals.

Now comes news that the Philadelphia Center City District (CCD) has asked the Federal Transit Administration (FTA) to waive its Buy America requirements for the "procurement of glass panels needed to construct two structural glass pavilions."

According to the waiver request, "no glass manufacturer had the capability to fabricate the glass panels in the United States. This is due to the size of the panels and the laminated glass make-up and edge polishing requirements."

Similar waiver claims have been made in the past. For example, a Chinese firm was contracted to supply welded steel sections for the Oakland Bay Bridge when it was reported that no U.S. manufacturers were able to supply the needed steel. In fact, several U.S. firms did indeed stand ready to supply the steel components. Unfortunately, the contract went to a Chinese company whose product subsequently proved faulty, necessitating costly delays for the overall project.

Spending federal tax dollars on Chinese-made products does little to aid the U.S. economy. Both Philadelphia's CCD and FTA officials should thoroughly review the waiver request, and actively seek out U.S. firms, before simply handing the project off to a supplier in China.

Read more about China's massive, actionable subsidies for its glass industry.