One month after a fire triggered a massive blast at a Texas fertiliser plant that killed 15 people, officials yesterday had to declare the cause of the blaze as “undetermined”.

A criminal investigation has been launched into the massive Texas fertiliser plant explosion that killed 14 people, after weeks of largely treating the blast as an industrial accident.

After days of waiting, the first group of people who fled their homes when a fertiliser plant exploded in a blinding fireball are to be allowed to return.

Residents displaced by the massive fertiliser plant explosion in Texas have been told by officials that tanks on the site are leaking gas and causing small fires.