The government shutdown has gotten so bad that agencies are using legal loopholes to restart critical functions

The government shutdown, which started December 22, forced many of the federal government's agencies to work with a bare bones staff and cease a slew of major functions.

But as the shutdown drags on, more and more agencies are starting to bring call employees back to work to restart some critical functions of government that were going untended.

The unprecedented nature of the closure is forcing government agencies to use legal loopholes to take unprecedented action to try to soften the blow from the shutdown.

During the shutdown, workers deemed "essential" - such as law enforcement or TSA agents - are compelled to work without pay during the duration of the shutdown.

The rest of the "nonessential" workers are placed on furlough, meaning those employees must stay home and do not receive pay.

Around 420,000 workers were deemed essential at the start of the shutdown, while 380,000 were furloughed.

But many agencies are starting to switch workers' classifications from furloughed to "excepted" status to get key operations running again. Here's a rundown of some of the agencies that are bringing back workers from furlough:

Some funding has been reallocated from other programs, discovered, or paid through fees to those agencies. Almost all of the workers will not get paid while they are back on the job until the shutdown ends, meaning the financial strain on these employees will continue.

Furloughed workers can apply for government unemployment insurance in some cases, while excepted workers may not.

Unions representing the various agencies' employees have argued that forcing the workers to come back to the job without pay is a violation of federal labor laws.

The National Treasury Employees Union, which also represents IRS employees, is suing the government for forcing the workers to come in without compensation.

"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," Tony Reardon, NTEU president, said in a statement.

On Tuesday, a federal judge blocked a lawsuit that sought to force the government to pay employees working without pay during the shutdown.