Zero Hedge is taking this seriously. In their detailed report yesterday in which they post a video showing the extraordinary violence of the explosion, they write:
Law enforcement officials stated that the cause of the explosion is currently under investigation. This incident adds to the increasing number of #food processing plants throughout the US experiencing #fires or, in this instance, devastating explosions.
https://www.zerohedge.com/markets/shocking-video-shows-chocolate-factory-explosion-pennsylvania