It seems that the fire was due to a pile of magic-prop flash-paper, which was improperly stored under the desk he was printing on. This is highly flammable stuff which should have been kept in a sealed metal box well away from any potential sparks or flames. It's a lot like the nitrocellulose film stock that used to cause theater fires in the silent film era: https://www.flinnsci.com/media/620948/91356.pdf Here's a video on another 3d printing forum which talks about this tragic incident, that's only peripherally related to 3D printing: https://www.3dprintingforum.org/foru...7-year-old-boy