Foreign workers are being imported to the United States to build auto plants, a recent investigation finds.

In an investigation by CBS News, researchers found that over the course of the last four years, foreign workers have been brought to the U.S.–most likely on the L-1 visa–to fill construction jobs.

The L-1 visa is for foreign workers who are employed by a multinational corporation. The workers are allowed to come to the U.S. after they’ve worked with the corporation abroad for a year. Every year, close to 80,000 foreign workers are imported to take jobs that Americans would otherwise do.

When researchers spoke with Gerald Greiner, a former manager for Germany contractor Eisenmann, he explained how a project back in 2013 for a U.S. auto plant caught his eye when he noticed foreigners on the job site:

“There was Polish and Slovenian and Croatian people there,” he told correspondent Vladimir Duthiers. “It was hard for me to believe because I just didn’t understand why they would be here.”

What did they do? “Anywhere from steel erection to pipe fitting to pouring concrete to installing equipment, just about everything.”

The cars would be built by American workers — but the building of the auto plants was being done by foreign workers. “Exactly,” said Greiner. “They come in at groundbreaking, they’re done at start of production.”

Duthiers asked, “Did you think to yourself that the jobs that these guys were doing could be done by Americans?”

“Oh yeah, absolutely. Yes.”

The CBS News crew ended up at an apartment complex in South Carolina that housed the workers building the auto plant. They primarily hailed from Eastern European countries like Slovenia and Croatia.

Sheet metals union worker Daniel Travancic told CBS News he is “angry” that blue-collar locals.

“There’s lots of guys out there still looking for work in the United States,” Travancic told CBS News. “And now we have how many thousands and thousands of East European workers working here, and they’re abused, too? Who lets this happen?”

John Binder is a reporter for Breitbart Texas. Follow him on Twitter at @JxhnBinder.