Seven former and current Walmart employees are suing the retail giant after one of its Pennsylvania stores installed a surveillance camera in a unisex bathroom used by employees and customers, according to ABC News.

The camera was allegedly installed by two employees in the company's loss-prevention department, with the aim of monitoring employees for theft.

They installed the device in a bathroom–dressing room in the Tire and Lube center of a Walmart Supercenter in Easton, Pennsylvania. Workers discovered the camera in March 2008. It's not known how long the camera was recording activity in the bathroom before it was found.

Walmart fired two employees who were responsible for installing the camera, according to a statement it provided ABC News. The suit also names four local Walmart managers.

The attorney representing the plaintiffs says three of the employees were dismissed from their jobs after complaining about the camera.

It's not the first time a company has been caught videotaping employee bathrooms. Workers at Consolidated Freightways discovered in 1997 that the trucking company had concealed surveillance cameras behind the mirrors in worker bathrooms in California. The company claimed it was trying to catch employees selling or using illegal drugs, and that the cameras were not aimed at the urinals or bathroom stalls.

Workers at the Sheraton Boston Hotel and Tower discovered in 1991 that their employer had been videotaping them in an employee locker room.

State laws vary on whether companies need to notify workers in advance that they're being monitored. Laws also vary on what kinds of surveillance companies can do. Some states explicitly prohibit the installation of cameras in bathrooms, changing rooms and other areas where people have a reasonable expectation of privacy.

But even without an explicit law prohibiting such monitoring, state tort laws can be invoked to protect the privacy of employees in cases where there is an expectation of privacy.

Photo: Casey West/Flickr