Toxic waste illegally dumped into a river in southern Johor state sickened scores of students and teachers, prompting Malaysia's government to order 111 schools to close Wednesday.
Education Minister Maszlee Malek earlier Wednesday told 34 schools to shut down and later said that number was up to 111 schools. He didn't give details.
More than 500 people were treated for breathing difficulties, dizziness, nausea and vomiting after inhaling toxic fumes from the waste. Officials said 166 people were hospitalized, and several were under intensive care.
Environment Minister Yeo Bee Yin was quoted by the country's Bernama news agency as saying that rain could have caused the contamination to spread despite efforts to contain it.
Two factory owners and a worker have been detained for investigation. News outlets said the waste, believed to contain chemicals used to dissolve metal at a scrapyard and a chemical factory, was discharged a week ago, leaving a thick black sludge in the river. Cleanup efforts are ongoing.