Chinese workers making touchscreens for Apple have urged the company to address the chemical poisoning that occurred in one of its contract factories.
Reuters news agency says it has seen a letter workers at Wintek sent to Apple.
The Taiwanese company that owns the factory says it used hexyl hydride from May 2008 to August 2009, but stopped after discovering it was making workers ill.
"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," said the letter.
The workers say they want assurances that, if they suffer fresh bouts of illness from the poisoning, they will receive adequate medical compensation.
"I hope Apple can respect our labour and our dignity. I hope they can stand up and apologise to us," one worker told Reuters.
A spokesman from Wintek told Reuters all staff who needed medical treatment because of the poisoning had been treated. The spokesman said the company has reverted to using alcohol to clean the panels that it manufactures for Apple.
This is not the first time Apple has been criticised for the conditions in some of its contract companies. Last year the company came under fire for a spate of suicides that occurred in Foxconn plants.