Apple’s 2017 WWDC conference is scheduled to be held in San Francisco, California.

According to The Verge, Apple has cancelled the conference due to a “serious incident” with a worker in the hall, which is scheduled for July 12.

A spokesperson for Apple did not immediately respond to The Guardian’s request for comment.

Earlier this year, a group of workers in a hall in China’s Shanghai city were killed after an air conditioning unit overheated, triggering a fire.

The incident came amid a spate of air conditioning fires across China.

The fires have been blamed on a faulty system at the plant.