Two Chinese nationals were arrested in Chachoengsao for the illegal possession of hazardous materials, the Natural Resource and Environmental Crime Suppression Division (NED) said.
NED police officers and Department of Industrial Works staff on Sunday raided a factory and arrested Chinese managers identified only as Guo, 55, and Li, 42, in Phanom Sarakham district of the eastern province.
Officers also confiscated a 10-tonne mound of waste and abandoned materials from a separation process that were contaminated with heavy metals, as well as two piles of crushed products which were also tainted with heavy metals.
The suspects were charged with possessing type-3 hazardous substances that were contaminated with lead, cadmium, mercury and other heavy metal substances, said the NED.
The arrest came after the Customs Department earlier seized 10 shipping containers, containing 256 tonnes of hazardous materials.
The police investigated and found the importer was the company located in Phanom Sarakham.
NED officers found the group also had a factory in Prachin Buri.
The factory had previously been ordered by the Department of Industrial Works to shut down, with evidence seized and banned from being transported.
But on Jan 5, police found the hazardous materials were being transported from the factory in Prachin Buri to the factory in Chachoengsao, which led to the raid yesterday.
The Department of Industrial Works has now ordered the factory in Chachoengsao to stop the operation.
The suspects accepted that they did not have permission to process the hazardous materials. Both confessed to the charge.
The pair were taken to Phanom Sarakham station in Chachoengsao for legal action.
Department of Industrial Works officials are inspecting the area and nearby communities before taking futher legal action, the NED said.
Lead and arsenic from the factory can contaminate the environment, and this will harm people and animals in the long run, the NED added.