Police have detained a director of Win Process Company Ltd and are questioning him about recent industrial-waste fires at warehouses in Ayutthaya and Rayong provinces.
More people are likely to be arrested in relation to the fires and illegal storage of hazardous waste.
Pol Lt Gen Thatchai Pitaneelabut, assistant national police chief, told Thai PBS on Wednesday that Opas Boonchan, director of Win Process, was arrested in Phetchabun province on Tuesday night and taken to Rayong early Wednesday morning.
He was detained over the recent industrial-waste fires at a Win Process warehouse facility in Ban Khai district of Rayong and at a warehouse reportedly rented by Aek Uthai Co in Phachi district of Ayutthaya province.
Mr Opas was reportedly arrested at Aek Uthai Co in Sri Thep district of Phetchabun.
Pol Lt Gen Thatchai said that detectives found links between the hazardous substance fires in Ayutthaya and Rayong. Before the fires, police had received complaints from residents about the storage of hazardous substances and the release of contaminating toxic substances.
Investigators believed the fire in Ayutthaya was set deliberately and were compiling the evidence in the Rayong case, which could also be arson, the assistant police chief said.
The waste had been put in storage instead of being properly disposed of as earlier expected, he said.
Detectives were checking if hazardous waste was illegally stored in other provinces, and were also following the trail of money linked to the business. Police planned to arrest more suspects linked to the fires, Pol Lt Gen Thatchai said.