Many more are feared injured in the explosion at the power base in Middletown, Connecticut, USA.
President Obama is being kept informed of the ongoing situation - but early reports do not indicate any terror links.
The eastern USA has been badly hit by blizzards this weekend - said to be the worst in a century.
Roads are closed, airports shut and power blackouts have been hitting tens of thousands - a situation which will not be helped by today's explosion.
Source:eveningstar.co.uk
