Apple and Google said they would work alongside the Competition and Markets Authority, insisting that they support choice in the market.

The UK’s competition watchdog will examine whether Apple and Google should be subjected to extra scrutiny over how they run their mobile platforms, in its second investigation under new digital markets regulations.

The Consumer Product Safety Commission said Thursday that Fitbit knew a defect in its Ionic smartwatches created an unreasonable risk of serious injury or death, as it had received numerous reports of the devices overheating while being worn and leaving some consumers with second- and third-degree burns.

Fitbit has settled with the U.S. Consumer Product Safety Commission (CPSC) over a longstanding defeat that caused some wearers to sustain burns. The deal finds the Google-owned fitness company paying a $12.