There is a risk of a BLEVE incident, (Boiling Liquid Expanding Vapor Explosion)
LNG expands 600 times when it vaporizes, and if a tank were ruptured out over water, it could create a pretty large fireball.
There has only been one terrorist attack on an LNG ship, (The Gas Fountain) and it was in the Persian Gulf, back in the 1980’s.
http://hormuz.robertstrausscenter.org/lng_tankers
An LNG ship was hit by an Exocet missile, and one of the tanks was ruptured. The crew safely abandoned ship, and
the fire was eventually extinguished. It didn't BLEVE. I believe that ship was repaired and put back in service.
In laboratory and open ocean combustion tests, there have been no documented cases of LNG BLEVEs. It is a theory that has never been capable of being produced and has been tested several times.
LNG SAFETY MYTHS and LEGENDS
http://www.netl.doe.gov/publications/proceedings/02/ngt/Quillen.pdf
Then this is CHANGE we can BLEVE in?.............