By Phuket Gazette
Officials surrounded the area with floating protection barriers to prevent more fuel oil from leaking from the vessel.
The old and decrepit boat had been anchored off Tapao Yai but was swept ashore by waves on Monday. Fuel remaining aboard started to leak.
The boat is one of six vessels anchored off the island since last year after their owners violated Thai law by leaving Thai waters and failing to report their return.
The owners were prosecuted and the boats abandoned.
The protection barriers extend 100 metres around the beached boat and officials have added neutralising chemicals that solidify the spilled fuel so it sinks to the sea bottom.