Apple has been under pressure by China Labor Watch and Green America since March over the use of benzene and n-hexane in manufacturing, because both have been linked to health problems and there are better alternatives. Benzene is a cleaning agent, and n-hexane is a solvent. Benzene is a carcinogen known to cause leukemia, and n-hexane has been linked to nerve damage. Apple conducted an investigation and found that only four of the twenty-two manufacturers used by Apple used the chemicals and all four kept the usage to within safety limits.
Despite this, Apple has mandated that the chemicals will be banned in the final stages of iOS and Mac product assembly. Although the chemicals can still be used in the earlier parts of the process, Apple has put limits on the amount of each that can be used; and, Apple has instituted mandates that all substances, even if they aren't supposed to contain either chemical.
Green America credited the move as "a good first step", while Lisa Jackson, Apple's vice president of environmental initiatives, said of the new policies: "This is doing everything we can think of to do to crack down on chemical exposures and to be responsive to concerns. We think it's really important that we show some leadership and really look toward the future by trying to use greener chemistries."