Apple Bans Two Toxins from iPhone Assembly Plants
Apple has banned the use of two chemicals that endangered the health of Chinese iPhone assemblers: n-hexane, which is used to clean screens and could cause nerve damage and paralysis; and benzene, a known carcinogen that’s used to coat electronic components. However, these chemicals are still in use further up in the supply chain, and Apple is being pressured to eliminate them from the entire chain.
Hexane is surprising. As a chemist we considered it safe. But we did not use it continuously like factory workers can. Once a month maybe. Benzene we did consider a problem and have for years.
From what I've read on it, it's fairly safe (you're exposed to it when pumping gas), but problems occur in industrial applications where there is continuous exposure.