At the University of Kentucky, incompatible wastes were accidentally mixed resulting in a fire and explosion. It is believed that nitric acid and halogenated organic solvents were involved, but the exact cause may never be known.
The explosion blew glass shrapnel across the laboratory. Students on the other side of the laboratory were hit with glass fragments, including at least one who reported that the glass bounced off his safety goggles.
Thankfully, this student was following the rule you must wear your safety glasses at all times in the laboratory even if you aren't "doing anything."
http://www.ilpi.com/safety/explosion.html