If you’ve ever noticed that your battery is draining abnormally quickly while using the Facebook or Messenger app on your iPhone, it might not be a coincidence. According to a former metadata specialist, the company has the ability to covertly drain the batteries of Android and iPhone users as part of internal app testing.

In an interview with The New York Post, George Hayward claims he was fired last November for refusing to participate in “negative testing” while working on the Messenger app. According to QASource, negative testing allows developers to “compare an expected result with an incorrect result” by showing how an application reacts to incorrect data. In the case of Facebook, negative testing can be used to see how certain features work, or how quickly messages load when batteries run out faster than expected.

Hayward, who filed the lawsuit but later withdrew due to an arbitration requirement, says the practice “could hurt someone” by draining the battery without warning. Hayward doesn’t say how many people may have been affected by the negative testing, or if the Messenger testing ever got out of beta. However, Hayward told The Post that he was provided with an internal training document called “How to Run Thoughtful Negative Tests” that provided examples of battery-draining experiments being done. He then claims that he was fired after three years at the company for refusing to participate in testing.

Facebook apps have long been blamed for draining iPhone battery. This 2020 Reddit thread showing the Messenger app using more battery than PUBG Mobile is just one of many examples.

It’s unclear from the report what the next steps in the lawsuit are and whether Facebook will be forced to respond. Hayward’s lawyer argues that his client supports claims of “clearly illegal” practices.