"He confirmed that the armed forces were on stand-by to provide assistance to the civil authorities if required."
Why would this be necessary if they were convinced it was just an accident. They've been saying there will be some more blasts and explosions but nothing to the magnitude of the initial one.
There's still more to this than what they're telling.
"Why would this be necessary if they were convinced it was just an accident."
That's one of the functions that the army fulfills. Similar to the way the National Guard might was used in the aftermath of Hurricane Katrina, for instance.
Because of the specialist equipment the army has for dealing with hazardous waste.
As in any emergency as in your country the military will be deployed to aid the civilian authorities if needed.