Chinese factory workers making touchscreens for Apple's iPhone and iPad devices have appealed for the company's help over a case of chemical poisoning.
The workers are employed by Wintek, the Taiwanese owner of a factory in the Suzhou industrial park in eastern China where hexyl hydride, also called n-hexane, was used to clean touchscreens between May 2008 and August 2009.
Wintek began using the substance, which evaporates more quickly than alcohol, to speed up the production of touchscreens - but stopped after it was found to be making workers ill. Symptoms are said to include sudden numbness in hands, swelling and pain in the feet, tiredness and faintness.
Apple admitted the chemical poisoning for the first time in a recent annual report on environment and working, which revealed that 137 workers had been hospitalised by n-hexane poisoning.
"This is a killer, a killer that strikes invisibly," the workers said in a Chinese-language copy of the letter, signed by five employees and shown to news agency Reuters. "From when hexyl hydride was used, monthly profits at Apple and Wintek have gone up by tens of millions every month, the accumulated outcome of workers' lives and health."
An English version of the letter has been sent to Apple. It is addressed to CEO Steve Jobs, who is on indefinite leave due to illness.
Workers at the plant in Suzhou are calling on Apple to step in, alleging that Wintek hasn't adequately compensated affected workers, and has put pressure on those who took compensation to give up their jobs.
Jia Jingchuan, a 27-year-old production technician who said he fell ill after using n-hexane at Wintek, told the UK's Guardian newspaper:
"I hope Apple can respect our labour and our dignity. I hope they can stand up and apologise to us."
Apple has declined to comment on the workers' letter.