This gives a good reason to ensure that no one attempts to use an E-cigarette onboard:
Man suffers fractured neck, third degree burns and has hole blown through the roof of his mouth after e-cigarette explodes - Americas - World - The Independent
End of the article, relates to the UK:
This summer a series of “highly disturbing” fires caused by exploding e-cigarette chargers led to a nationwide safety alert in the UK, with more than 100 fires thought to have been caused by the devices in the last two years.