The well, located behind a fire station in the southern part of Carlsbad, blew out Thursday when a drilling crew punctured it.
Police evacuated 462 homes as well as nearby offices and a few motels. There were no injuries.
On Sunday, authorities checked identification of returning residents and distributed health and safety information.
Meanwhile, crews continued to burn off the leaking gas and tried to cap the well, said Liz Baggs, Carlsbad's emergency preparedness manager.
``They're going to be working on it for about 30 days,'' she said.
The crews had been working through the night and into Sunday morning to flare off the spewing natural gas, creating a 200-foot fireball that could be seen 5 miles away.
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