More than 130 workers at a Chinese factory making touch screens for Apple iPhones were poisoned by a toxic chemical in 2009, the Taiwanese company said on Thursday.
Labour activists have previously raised concerns about conditions in Chinese factories producing iPhones, arguing that employees endure long hours, low pay and high pressure.
In the latest revelation, an official from Wintek Corp told AFP that 137 workers were poisoned at the factory in China's eastern Suzhou city in 2009.
The official, who declined to be named, said that "one worker still needs regular outpatient clinic diagnosis and care" but that others were no longer receiving medical attention.
They were exposed to a toxic chemical agent known as n-hexane, which was used to clean glass screens of the iPhone.
"We've stopped using n-hexane, and the cleaning agent has been substituted with alcohol, even though it is less effective," the official said.
He said some of the workers had received up to 100,000 yuan ($15,000) in compensation.
Another Taiwanese firm, Foxconn, which makes electronic goods for Apple and other Western technology firms, saw a spate of suicides at its Chinese plants last year.