"My legs are always in pain and swelling," he said by phone on Monday. "I worry my condition will get worse."

Guo was one of 137 workers U.S. tech giant Apple said was exposed to n-hexane, a chemical cleaning agent that was used at one of its supplier's factories in Suzhou, China. The case was addressed in Apple's most recent progress report on its suppliers, with the company saying that "all affected workers have been treated successfully."

But that statement contradicts with the accounts of two factory workers, who say they still need medical treatment. In interviews, they said they are being told by the supplier they must quit their jobs in order to receive the compensation for the treatment.

"I'm not satisfied at all with how things have been handled," said Jia Jing Chuan, another worker at the facility who was exposed to the chemical poisoning. "We hope Apple will move things forward and do something about this."

The Suzhou factory is operated by Taiwanese company Wintek, a producer of touchscreens. Apple said it had learned about the chemical poisoning in 2010 and subsequently required Wintek to stop using the n-hexane and make changes to its ventilation system.