The blast occurred around 6:15 p.m. at the resort located at 2481 Kaanapali Parkway, News.Az reports, citing foreign media.
Web cam footage captured debris flying from the building. Bystanders with medical and first responder experience assisted police until paramedics and firefighters arrived on the scene.
The victims, aged 18 to 74, were treated at the scene, and one person was airlifted to Maui Memorial Medical Center for emergency care.
Debris was still scattered all along the beach late into the night, and investigators put up yellow flags to mark them.
Preliminary investigations suggest that the explosion may have involved liquefied petroleum gas, which supplies common area BBQs, police said. Witness statements indicate a possible grill malfunction before the incident.
The official cause remains undetermined and is under active investigation.
No evacuations were necessary and there was no additional threat, police said.
