A 26-year old decided to have a cup of coffee. He  took a cup of water and put it in the microwave to heat it up  (something that he had done numerous times before). I am not sure how  long he set the timer for, but he wanted to bring the water to a boil.
 
When the timer shut the oven off, he removed the cup from the microwave. As he looked into the cup, he noted that the water  was not boiling, but instantly the water, in the cup, "blew up" into his  face. The cup remained intact until he threw it out of his hand but all the water had flown out and into his face, due to the build up of energy. His whole face was blistered and he had 1st and 2nd degree burns, to his face which may leave scarring. He also may have lost partial sight, in his left  eye.
 
While at the hospital, the doctor who was attending to him stated that this is fairly common occurrence and  water (alone)should never be heated, in a microwave oven. If  water is heated in this manner, something should be placed in the cup to diffuse the energy such as: a wooden stir stick, a tea bag, etc. It is however a much safer choice to boil the water in a tea kettle.
 
General Electric's response:
 
Thanks for contacting us. I will be happy to assist you. The e-mail that you received is correct.  Micro-waved water and other liquids do not always bubble, when they reach  the boiling point. They can actually get superheated and not  bubble at all.
 
The superheated liquid will bubble up out of the cup when it is moved or when something like a spoon or tea bag is put into it. To prevent this from happening and causing injury, do not heat any  liquid for more than two minutes, per cup. After heating, let the cup stand  in he microwave for thirty seconds before moving it or adding anything  into it.
 
If you pass this on ... you could very well save someone from a lot of pain and suffering.
 
Now check the attached video clip and see for yourself what can happen!

Regards