Oil mystery at sea — DSI probes 9 firms over 60m litres missing
DSI investigates nine shipping firms after 57–60 million litres of oil reportedly vanished during transport in the Gulf of Thailand
Thailand’s Department of Special Investigation (DSI) has launched a probe into nine companies linked to oil tanker operations after an estimated 57–60 million litres of fuel reportedly went missing during transport in the Gulf of Thailand.
The investigation follows summonses issued to eight tanker-owning firms as witnesses, with a ninth company, identified as a vessel leasing firm rather than an owner, later brought into the inquiry. The case centres on irregularities involving 20 shipping trips conducted by 12 vessels transporting oil from refineries in the eastern region, with the disappearance reported off Surat Thani.
Authorities are examining possible offences under the Price of Goods and Services Act B.E. 2542 (1999), including alleged stockpiling, transport delays, and refusal to distribute fuel. Companies were required to provide information to investigators by April 30, 2026.
Pol Lt Col Woranan Srilam, director of the Consumer Protection Case Division at the DSI and head of the investigative team for special case No. 59/2569, said representatives from all nine firms have now been questioned.
Initial findings show two primary contracting models for oil transport. In some cases, refineries handle both origin and destination logistics and arrange vessels according to transport plans. In others, destination companies either source vessels independently or request the refinery to do so.
Companies have cited three main reasons for delays in voyage times. These include hydrographic constraints such as tidal conditions preventing docking, mechanical issues requiring repairs before port entry, and congestion at unloading points where other vessels were still transferring oil or storage facilities were full.
The Thai Maritime Enforcement Command Center (Thai-MECC) has submitted navigation analysis reports to investigators. The DSI is now comparing testimony from the companies with maritime data and may seek further technical details from Thai-MECC next week, particularly regarding extended voyage durations.
Investigators have not ruled out summoning additional agencies, pending further conclusions on each issue.
Separately, Thitipas Chotedechachainan, a former Bangkok MP and head of an energy reform oversight panel, along with legal representatives, has submitted 166 transport documents flagged as irregular. These relate to fuel shipments from oil depots in Rayong and Chonburi to destinations in Surat Thani, Chumphon and Songkhla during March 2026.
Authorities are reviewing whether the case meets the criteria to be accepted as a special case. If not, it may be transferred to the Royal Thai Police. However, investigators may still open a preliminary inquiry if grounds for suspicion are established.
In a related matter, special case No. 66/2569 concerning alleged fuel adulteration in Ang Thong province is also under investigation. The DSI director-general has assigned Pol Lt Col Nirut Pattanarat, a specialist in special cases, to lead the inquiry, which is currently focused on gathering evidence.
