The incident took place about two to three nautical miles off the island. Boats nearby were dispatched to the scene of the accident to rescue passengers who jumped into the sea, according to the Facebook page of the Disaster and Mitigation Special Unit.
All 108 members on board – 97 Thai and foreign passengers, and 11 crew – were taken to the shore at 8am. The fire in the boat was brought under control by 8.20am.
Ten passengers were sent to Koh Tao Hospital for treatment. Nine passengers suffered symptoms from inhaling the smoke, but one Myanmar worker broke his arm after jumping off the boat.
Even though officials have extinguished the fire, the heat inside the passenger boat made it difficult to survey the damage, said Koh Tao Police Station superintendent Pol Colonel Chokchai Suthimek.
He added that police officers would collect evidence and interrogate the persons involved to find out the reasons behind the incident.
Pramuan Tessana, director of the Regional Harbour Office in Surat Thani, said that the fire likely originated in the engine room. Many parts inside the room could cause a fire, such as the water pump, electricity generator, motor and fuel, he added.
The boat had received certification for sailing readiness from the Regional Harbour Office in Chumpon province, he said, adding that the boat was equipped with fire extinguishers in line with the office's requirements.
The office will set up a committee to investigate the case, which could take 30 days, he said.
The mayor of Koh Tao subdistrict, Watcharin Fasiriporn, assured that the incident had not affected tourists' confidence in travelling to Koh Tao as many boats were ready to serve them.
However, he admitted that the incident would affect the transport of products between the island and the mainland. "Boat operators have repaired spare cargo ships to mitigate the impact on transportation," he said.