If you’ve ever noticed your battery draining abnormally fast while using the Facebook or Messenger app on your iPhone, it might not be a coincidence. According to a former Meta data scientist, the company has the ability to secretly drain users’ Android and iPhone batteries as part of its internal app testing.

In an , George Hayward claims he was fired last November for refusing to participate in “negative testing” while working on the Messanger app. According to , negative testing lets developers “compare the expected output against the incorrect output” by revealing how an app responds to invalid data. In Facebook’s case, negative testing could be used to see how certain features work or how quickly messages load when batteries are drained more quickly than expected.

Hayward, who filed a lawsuit but later withdrew it due to an arbitration requirement, says the practice “could harm somebody” by depleting their battery without warning. Hayward doesn’t say how many people may have been impacted by the negative testing or if the Messenger testing ever made it out of the beta stage. However, Hayward told the Post that he was given an internal training document titled, “How to run thoughtful negative tests,” which included examples of battery-draining experiments being carried out. He then claims he was fired after three years with the company for refusing to participate in the testing.

Facebook apps has long been accused of causing iPhone battery drain. This from 2020 that shows 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 or if Facebook will be forced to respond. Hayward’s lawyer contends that his client stands by the allegations of the “clearly illegal” practice.