Tax season is right around the corner, which means the Internal Revenue Service gets extremely busy. But because of the government shutdown, the majority of IRS employees were furloughed. With no end to the shutdown in sight, the IRS had to call back 46,000 employees, roughly 60 percent of the agency's workforce, to come back to work to process refund payments. The kicker? They're going back to work without pay.

The union that represents IRS employees, the National Treasury Employees Union, filed a lawsuit last week challenging the Trump administration's decision to call back those who were furloughed, saying the "Antideficiency Act violates the Appropriations Clause of the Constitution, which does not allow the government to obligate funds that have not been appropriated by Congress."

The union is also challenging the need for furlough employees to come back to work without pay because their jobs don't protect human life and property, like a law enforcement officer does.

“There is no doubt the IRS needs to get ready for the 2019 filing season that starts Jan. 28, and IRS employees want to work. But the hard, cold reality is that they’ve already missed a paycheck and soon they’ll be asked to work for free for as long as the shutdown lasts,” NTEU National President Tony Reardon said in a statement. "I’m worried whether these employees will have the money to put gas in their car to get to work. I’m worried that highly trained IRS employees will consider quitting so they can get a job that actually comes with a paycheck."

A federal judge on Tuesday denied the union's request to force the government to pay employees who have been called back to work, the Associated Press reported.