I'll never forget organic chem lab. Day after day of ether. Fell asleep a couple of times on the bus on the way home and it was only a 15 minute ride.
Our professor told us how they used to wash their hands in benzene until somebody noticed that the incidence of certain cancers was much higher in lab personel than the general populace and was able to trace it back to high levels of benzene in their bodies. What's really serious is how everything is labled as dangerous in labs now days; so, you stop taking any of the warning labels seriously. If I had known how low of a dose of carbon tet was carcinogenic and how low of a dose was lethel, I wouldn't have handled it without gloves. But, when even the D.I. water is labeled you tend to ignore the labels.
