A cordon remains in place around the Mt Maunganui house where a P-lab exploded early this morning, critically injuring one man.
Police said the section of Ocean Beach Rd which had been closed to traffic had reopened.
Waikato Hospital said a 57-year-old man burned in the blast was still in critical condition in the intensive care unit.
The man, who received burns to his torso and head, was rescued by firefighters following the explosion just before 4am.
A second man fled the house and was found at a nearby home.
About 10 surrounding houses were evacuated, but most residents were able to return to their homes later in the morning. Most said they did not hear the blast.
Police inspector Karl Wright-St Clair confirmed police were dealing with a P lab.
"We believe the lab was operational at the time of the explosion'', he said.
The investigation is focussing on the basement, and the police officers who arrived first at the scene went through a decontamination process.
No arrests had been made.