Apple has banned the use of two chemicals, benzene and n-hexane, in final assembly of its iPhones and iPads, the Associated Press reports. The company has drawn criticism in the past for using both potentially hazardous chemicals — workers reported n-hexane-related sicknesses in 2010, and by 2011, workers at an Apple manufacturing partner wrote a letter regarding their concerns and health issues due to n-hexane exposure. Though Apple claims an investigation…