The explosion, on board the 45-foot motoryacht Serenity, under repair on the hardstand at the marina, ripped through the air at about 2pm, according to witnesses.
Kusoldharm rescue workers called to the scene arrived to find two workmen, both employees of M.T.T. Marine Engineering Co Ltd, on board unconscious.
Chakkri Sawekwang, 31, from Nakhon Sri Thammarat, remained unconscious and unresponsive. Rescue workers performed CPR on Mr Chakkri while he was still on the boat then rushed him to Vachira Phuket Hospital.
The first-responders managed to revive the other workman, who gave his nickname as “Got”.
Mr Got said that explosion came from below deck. A red extinguisher was found on the main deck of the boat, where the two workmen were found.
Rescue workers did not report any serious burns or broken bones on either of the two men.
Police have arrived at the scene and an investigation into the explosion is underway.
Wicky Sundram, Executive Director at Phuket Lagoon, told The Phuket News, “We have inspected the site to make sure it is safe, and we are still looking into what caused the accident.
“Our main concern is safety and that the two workmen are okay. They were both outside contractors brought in to work on the boat. They were not workers from any of the businesses resident here at Boat Lagoon.
‘To this we must stress to any persons who bring in outside workers to emphasise the importance of safety to these contractors,” he added.