Last week, when Apple released its annual review of labor conditions at its global suppliers, one startling revelation stood out: 137 workers at a factory here had been seriously injured by a toxic chemical used in making...the iPhone. Apple, describing it as a “core violation” of worker safety, said that it had ordered the contractor to stop using the chemical and to improve safety conditions at the plant. Apple also said that it would monitor the medical conditions of those workers. But in interviews...nearly a dozen employees who say they were harmed by the chemical said they had never heard from anyone at Apple. Instead, they said the contractor...Wintek...had pressed...workers to resign and accept cash settlements that would absolve the factory of future liability...[A] Wintek spokesman denied that...[and] even suggested that Wintek would pay for medical care should the symptoms persist after workers resign...Kristin Huguet, a spokeswoman at Apple’s headquarters...declined to discuss the Wintek case but said the company was committed to the highest standards of social responsibility in its supply chain. “We require our suppliers to provide safe working conditions, treat workers with dignity and respect and use environmentally friendly manufacturing processes whenever our products are made,” she said...