Technology giant Apple has accepted that workers in China became seriously ill when their factory illegally swapped a cheaper toxic chemical, according to the Apple Supplier Responsibility 2011 Progress Report released last Tuesday.

The company supplies touch screens to Apple Computer for their iPad and iPod products.

In 2010, we learned that 137 workers at the Suzhou facility of Wintek, one of Apple's suppliers, had suffered adverse health effects following exposure to n-hexane, a chemical in cleaning agents used in some manufacturing processes. We discovered that the factory had reconfigured operations without also changing their ventilation system. Apple considered this series of incidents to be a core violation for worker endangerment, the report said.

To prevent future incidents at this facility, we required Wintek to work with a consultant to improve their Environmental Health and Safety processes and management systems. We are monitoring the implementation of these corrective actions and preventive measures, and will conduct a complete reaudit of the facility in 2011, it added.

In parallel, Apple has verified that all affected workers have been treated successfully, and we continue to monitor their medical reports until full recuperation. Following China law, Wintek has paid medical treatment, meals, and foregone wages for sick or recuperating workers. A majority of the 137 workers have returned to employment at the same factory, the report said.

The report said that all 137 affected workers had been treated successfully at Wintek's expense, and that most of them had returned to work at the same factory.

Apple released the ASRR last Tuesday, acknowledging inadequate safety provisions at some factories.