Imagine how big you could get in a zero-g environment.

A Japanese couple who sold lucky charms guaranteed to glow for more than a decade were forced to stop after it was discovered that the charms were radioactive. The pair, ironically based in Hiroshima, imported tritium from Britain for the charms. Unfortunately they used 27 times more tritium than is allowed under Japanese law. It seems to me that the people who have to constantly fight Godzilla would make it harder for someone to order radioactive materials.