The new 142,000 square foot Wal-Mart is seen hours before the grand opening in Chicago, September 27, 2006. REUTERS/Joshua Lott Thousands of Wal-Mart employees are fighting to get their jobs back after Wal-Mart suddenly closed five stores last week without warning.

The retailer said it closed the stores in California, Texas, Oklahoma, and Florida because of persistent plumbing issues that could take as long as six months to fix.

More than 2,200 workers were laid off as a result and given two months of severance pay.

But some critics are skeptical that Wal-Mart closed the stores because of plumbing issues.

Officials in the five cities in which Wal-Mart closed stores say the company hasn't sought permits for plumbing work, according to ABC News. Additionally, a Wal-Mart plumbing technician who worked at the now shuttered store in Brandon, Florida, told WFLA that even if the store is replacing its entire sewage line, the work shouldn't take as long as six months.

The UFCW — a labor group representing Wal-Mart's laid-off workers — contends that the company closed the stores in retaliation against workers organizing for better pay, which is something Wal-Mart has been found guilty of doing in Canada.

The group has filed a claim with the National Labor Relations Board demanding that the company rehire the employees.

The UFCW isn't alone in its skepticism.

The closures have also fueled a bizarre conspiracy theory that the US military is planning to enact martial law this summer under the guise of a Special Operations exercise called Jade Helm 15.

According to the theory — which has no apparent basis in reality — the military will use the shuttered Wal-Mart stores as "processing" facilities for Americans once martial law is hatched.

—Milk N Cookies (@milkncooks) April 15, 2015

A video raising suspicions about this theory has been watched nearly half a million times since it was posted two days ago. The video shows police cars outside the store's loading docks and says the store has covered its windows with black tarp.

"Something sinister is going on at Wal-Mart and there's a big reason for them to be hiding what that is," writes the blog All News Pipeline, which posted the video. "Could these monstrous buildings with underground tunnels be transformed into something out of our worst dreams?"

Wal-Mart says the closures have nothing to do with Jade Helm.

"There's no truth to the rumors," Wal-Mart spokesman Lorenzo Lopez told Business Insider. Wal-Mart hasn't sought plumbing permits yet because the company is still considering additional upgrades to the buildings and wants to file all necessary permits simultaneously, Lopez said.

Critics began questioning the Jade Helm exercise after a military map was leaked that showed certain US territories marked as "hostile."

But the language is only for the purposes of the exercise, The Washington Post reports.

"The military has routinely launched exercises in the past in which regions of the United States are identified as hostile for the purpose of training," The Post's Dan Lomothe writes.