The Department of Disease Control is asking factory owners to strictly comply with disease control measures, warning that many plants with hundreds of workers fail to do so and risk spreading COVID-19.
Director-general Suwannachai Wattanayingcharoenchai said on Friday that 1,386 factories had been surveyed through the Thai Stop Covid Plus platform as of Tuesday.
The survey found that 1,056, or 76%, of them complied with disease control measures, but the remaining 330 (24%) failed to do so.
There were 250 COVID-19 cases at five factories in Samut Prakan, Prachuap Khiri Khan, Pathum Thani, Samut Sakhon, and Nonthaburi provinces.
Most of them employed more than 500 workers, their workplaces were poorly ventilated and there was more than one person per four square metres of space, Dr Wattanayingcharoenchai said.
COVID-19 spread mainly at factories where employees did not have their health checked each day before work.
Workers also partied and shared cups of water and their dormitories did not comply with disease control measures set by the Public Health Ministry, he said.