I worked at a semiconductor factory in the US for five years. I'm glad it wasn't in Photolithography -- that end of the fab reeked of acetone. My end had arsenic, but it was pretty well contained unless you went into the bead blast room. We also had elemental phosphorous, which has a tendency to explode if you look at it funny. Wets has hydrofluoric acid. CVD uses tons of silane, which is not only toxic but explosive. You really can't do without these chemicals if you want to have semiconductors. At best, you can stay away from the really carcinogenic resist chemistries. But just try to make an NMOS transistor without arsenic for the source and drain!
Edit: This is not to say that it's OK to destroy people's health to make semiconductors. Toxic chemicals are unavoidable in semiconductor manufacturing, and we need to handle them properly even if it causes a rise in prices.
Edit: This is not to say that it's OK to destroy people's health to make semiconductors. Toxic chemicals are unavoidable in semiconductor manufacturing, and we need to handle them properly even if it causes a rise in prices.