Science experiments can be very dangerous.  That's why it's recommended that they only be conducted by professionals in lab coats with beakers and things.  I can't imagine the thought process that led up to experimenting with fire with preschoolers, and yet here we are.

KSLA reports that 12 students at the Yellow School in Houston were injured when an experiment involving changing the color of fire (warning!) exploded, hurtling burning chemicals at the class gathered (too close) around to witness the action.  The color-changing effect is achieved by adding various combustible materials to the fire.  When the desired color didn't appear, the decision was made to simply "pour more of the pretty burning powder" in the fire.  I feel like someone skipped a little reading in the safety section of the manual.  What happened next is what officials call a "Flash Burn," and wind may have played a factor.

Of the the 12 kids hit with burning chemicals, 6 were transported to an area hospital to be treated for burns.  Fire and police officials are investigating.