Honolulu Fire Department investigators say welding equipment ignited diesel fumes that sparked an explosion on a fishing vessel at Pier 36 on Friday.
Five men were injured in the explosion – two suffered critical burn injuries and three others suffered serious burn injuries.
"Our initial crews came and we sent two ambulances and a district chief. Upon their arrival, they did find people severely burned on the pier. As they started examining the patients and doing triage, there actually ended up being five people that were injured in this explosion," Honolulu Emergency Services Department Director Dr. Jim Ireland said on Friday.
On Monday, fire investigators said they determined the explosion originated at the port side fuel tank. The vessel, Kim Thu, was a foreign long-line fishing boat.