Of the patients, five of them have cadmium levels in their urine that are higher than what is considered safe, according to Dr Surawit Sakdanuphab, Samut Sakhon public health chief.
Inhaling high levels of cadmium damages the lungs and can cause death. Cadmium can also be carcinogenic if it seeps into water sources.
The public health office has been testing people residing around the factory of J&B Metal Ltd after police earlier this month found that it was one of two factories in the province that was storing smuggled cadmium waste from an ore smelter in Tak province.
Tests on community members around the second factory, belonging to Sin Hong Cheng Inter Tech Ltd, found no sign of cadmium poisoning, said Surawit.
He added that 21 employees of the first factory who had been hospitalised on April 4 for treatment of cadmium exposure have been all discharged. Of them, seven had shown high levels of cadmium and four had displayed symptoms of anaemia.
Health officials will continue to monitor their symptoms as they continue their normal lives at home, he said.
Surawit said the public health office would on Sunday (April 21) hold a public meeting with community members in Soi Kong Phanan Phol, where the factory is located, to educate locals about the danger of cadmium and how to prevent exposure.
Earlier this month, people living near Tak’s Bound and Beyond Plc zinc smelting company, which ceased operating decades ago, alerted officials that the hazardous waste had been dug up.
Upon checking, officials found that 13,000 tonnes of cadmium waste had been moved from where it had been buried and tracked it to J&B Metal’s factory in Samut Sakhon. Upon only finding 2,500 tonnes of cadmium there, the officials went hunting for the remainder and found 6,000 tonnes in a factory in Chonburi’s Ban Bueng district and another 1,000 tonnes in a second factory in Samut Sakhon.