The Thailand Department of Special Investigation (DSI) has ordered a key suspect tied to a sprawling fuel adulteration operation to appear on June 8 to answer formal criminal charges, marking a significant step in one of the kingdom's most complex energy fraud probes. The summons targets Surat Sukcharoenkraisri, younger brother of prominent businessman Somboon Sukcharoenkraisri, known in commercial circles as "Sei Tue Cosmo," for his alleged central role in illegal fuel blending and overpricing through Trillion Petroleum Trading Co Ltd in Ang Thong province.
Why This Matters
• 57M litres of fuel vanished in Surat Thani alone—more than half the country's daily diesel, gasoline, and gasohol consumption—during transit between refineries and distributors.
• Penalties under the Fuel Trade Act include up to 5 years in prison and fines reaching 500,000 baht for adulteration; noncompliance with Prime Minister's reporting orders carries 10 years and 100,000 baht in fines.
• 166 maritime fuel transport documents from six domestic refineries are under DSI scrutiny for failing to meet regulatory requirements.
• Over 50B baht in losses have been absorbed by the Oil Fuel Fund to subsidize fuel prices amid widespread hoarding, smuggling, and adulteration.
Understanding the Oil Fuel Fund
The Oil Fuel Fund is a government mechanism designed to stabilize fuel prices and protect consumers from market volatility. When global energy prices spike, the government uses this fund to subsidize retail prices at the pump, preventing sudden increases that would burden households and businesses. In this case, the fund has absorbed losses exceeding 50 billion baht while investigators work to dismantle fraud networks draining the supply.
The Web Behind Trillion Petroleum
Surat Sukcharoenkraisri does not appear on any official registry as a director or shareholder of Trillion Petroleum Trading Co Ltd, yet financial and logistical analyses conducted by DSI investigators point to his significant operational control over the company's fuel distribution activities. The DSI accepted the Trillion case as Special Case No. 59/2025 in April, focusing on allegations that the Ang Thong depot systematically adulterated fuel to alter its quality from regulatory standards and failed to report oil movements and stock discrepancies.
Random fuel sampling at the Ang Thong facility confirmed adulteration, and authorities have already filed charges against the company and one of its registered directors. The summons to Surat represents an escalation, with investigators preparing charges that include jointly operating as unlicensed fuel traders, adulterating fuel in quantities exceeding 200 litres, and violating Prime Minister's Orders requiring daily reports on fuel stocks and movements.
A National Crackdown with Multiple Fronts
The Trillion investigation is one of four major fuel-related cases the DSI is currently handling under the leadership of Director-General Pol. Maj. Yutthana Praedam. The agency's broader enforcement effort encompasses fuel hoarding in Surat Thani, maritime transport irregularities, and market manipulation across the kingdom. Authorities have documented an unexplained surge in domestic fuel consumption by nearly 20M litres per day without corresponding increases in economic or industrial demand, a red flag pointing to large-scale hoarding and diversion.
In Surat Thani alone, investigators traced shipments totaling 217M litres dispatched from southern depots, but only 160M litres arrived at their destinations. The DSI is now summoning owners of eight shipping companies linked to discrepancies in 20 maritime oil shipments from eastern Thailand. Six large Section 7 fuel depots—major facilities classified under fuel storage regulations—in Surat Thani are suspected of deliberately hoarding supplies, having received more fuel than they sold in March—a potential violation of the Price of Goods and Services Act, which carries penalties of up to 7 years in prison.
Nationwide, legal action has been initiated against six domestic oil refineries and numerous major distributors accused of intentionally delaying diesel distribution and stockpiling fuel to profit from rising prices. During this period, 29.2M litres of diesel—representing 20.2% of the supply—temporarily disappeared from the distribution system. The DSI identified 23 large fuel tanker voyages totaling 50.8M litres with allegedly delayed delivery schedules, and 662 truck trips carrying 2.1M litres without clear destinations, suggesting off-system storage.
What This Means for Residents
For motorists and businesses in Thailand, the crackdown signals both relief and an acknowledgment of how deeply the problem has affected daily life. Adulterated fuel can damage vehicle engines, reduce fuel efficiency, and void warranties, costing consumers thousands of baht in unexpected repairs. The Oil Fuel Fund has absorbed losses exceeding 50 billion baht while subsidizing fuel during the crisis, a cost ultimately borne by taxpayers.
Protecting Yourself from Adulterated Fuel:
If you suspect you've purchased low-quality fuel, take these steps immediately:
• Retain your receipt with the station name, date, and time of purchase
• Note the fuel type you purchased (diesel, gasoline, or gasohol grade)
• If your vehicle shows signs of engine trouble—difficulty starting, loss of power, unusual noises, or increased fuel consumption—report the issue to both the service station and your vehicle manufacturer promptly. This documentation is essential for protecting your warranty claim.
• Consult your vehicle's service center to assess any damage and determine if warranty coverage applies
• Report the incident to the Department of Energy or local consumer protection authorities if you believe you received adulterated fuel
Fuel You Can Trust:
While the investigation continues, residents should prioritize fuel from established, major brands and well-known service stations with transparent supply chains. Avoid filling up at unmanned or poorly maintained facilities when possible. If you regularly commute long distances or depend on your vehicle for business, keep detailed fuel purchase records and monitor your vehicle's performance closely.
The Prime Minister has publicly condemned the "evil" fuel smugglers, emphasizing that their actions amount to excessive profiteering during a global energy crisis and contribute to fuel shortages across the country. The DSI's aggressive pursuit of suspects, including summoning eight of ten companies suspected of hoarding between March 21 and 25, reflects a coordinated response aimed at restoring market integrity and consumer confidence.
Broader Enforcement Landscape
The Trillion case is just one thread in a tapestry of fuel-related crimes uncovered this year. In Chonburi, three trailer drivers were charged in January for stealing 3.6M baht worth of diesel (126,000 litres) from Pattamwat Petroleum Co., Ltd., siphoning off B-0 diesel—a specialized industrial diesel grade—and replacing it with water before transporting it to an offshore oil rig. In Songkhla, a foreign logistics company owner and site caretaker face charges for illegally stockpiling approximately 85,000 litres of diesel without proper documentation under the 1999 Fuel Control Act.
Even individual scams have surfaced. A couple in Hat Yai and Phatthalung provinces were arrested in April for using doctored bank transfer slips—altered via mobile app—to obtain free petrol and meals. The man confessed to theft by deception, forgery, and use of forged documents. Meanwhile, in Ubon Ratchathani, a police investigator faces misconduct charges for allegedly demanding "fuel money" from complainants in connection with official duties.
Near the Myanmar border in Kanchanaburi, a 25-year-old Myanmar national was arrested in March for attempting to smuggle 120 litres of diesel out of Thailand, charged with exporting goods without customs procedures and illegal entry.
Accountability and Recovery
The DSI's methodical approach—analyzing financial records, maritime transport logs, and supply chain documentation—illustrates the complexity of dismantling entrenched fuel fraud networks. The agency is scrutinizing 166 maritime fuel transport documents from six domestic refineries that reportedly failed to meet regulatory requirements, including incomplete shipment records. This forensic work is essential to establishing criminal liability and ensuring convictions that send a deterrent signal.
Legal proceedings are being initiated against depots and 23 specific fuel transport shipments for withholding supply, and against transport operators for non-compliant shipping documentation. Charges will be filed under laws on price controls, fuel trade regulations, and unfair commercial practices, carrying penalties of imprisonment, fines, or both.
For consumers, the crackdown offers a measure of accountability. The government's willingness to pursue high-profile suspects like Surat Sukcharoenkraisri and to challenge major refineries and distributors demonstrates a commitment to market transparency. The June 8 summons is a test case: if convictions follow, it will signal that even those operating behind the scenes of legitimate businesses can be held responsible for orchestrating adulteration and price manipulation.
The Thailand energy sector's integrity depends on rigorous enforcement of fuel standards and supply chain transparency. With the DSI actively tracing missing fuel, summoning company owners, and preparing criminal charges, the agency is working to restore trust in a market shaken by widespread fraud. Whether these efforts result in lasting reform will depend on sustained political will and the ability to secure convictions against well-connected suspects in the months ahead.
