From the looks of it my guess is that someone dropped a full toner cartridge maybe? I Googled if the cartridges can explode and saw a Reddit post from a tech saying that they can explode but it’s very rare and difficult, and if it does it would fill up the inside of the copier with toner.
Also toner powder is really nasty stuff and is a carcinogen. I would not want to be anywhere near that room.
