A crack has relieved some pressure in a damaged chemical tank and the temperature of the highly flammable gas inside is continuing to fall, leading authorities to say Monday they believe the risk of a catastrophic explosion has been eliminated.

The risk of a catastrophic explosion at a damaged chemical tank in Southern California has been eliminated following a close overnight inspection that confirmed a crack in the tank relieved pressure a...

Covey said the results of overnight evaluation of the tank — that the temperature inside had dropped and that pressure had been released — was “incredibly positive news.”