The Coronene blog brought up a familiar subject - the solvent exposure. I am not a tox expert myself – but I guess that after few years in the lab one can rank the most-commonly used solvents according to the seriousness of their long-term exposure effects. So here it is the list:
Almost drinkable: EtOH, i-PrOH, acetone, DMSO, 1,2-propylene glycol
Tolerable: MeOH, EtOAc, butanols, THF, TBME, ether, pentane, heptane, cyclohexane, DMAc, AcOH, NMP, tetramethyl urea, sulfolan
Unhealthy:DCM, toluene, hexane, acetonitrile, ethylene glycol, formamide, DMF, nitromethane, 1,2-dimethoxyethane, trifluoroethanol, benzotrifluoride
Just Bad: Dioxane, benzene, chloroform, 1,2-dichloroethane, pyridine, p-xylene, methoxyethanol, ethoxyethanol, TFA, trichloroethylene, tetrachloroethylene, allyl alcohol, chlorobenzene, biphenyl+diphenyl ether (aka Dowtherm), o-DCB
Gangsta Badass: HMPA, CS2, CCl4, nitrobenzene
Chemists in synthetic labs should probably have their liver tests and blood count done once a year, to pick up any problem signs related to the chronic exposure. Women in early stages of pregnancy have to be particularly careful when working with organic solvents. Lots of factors can influence relative rates of oxidative metabolism and harmfulness of many solvents (like dioxane, benzene, hexane, glycol, chloroform etc) is due to the products of their oxidative activation. Some individuals are bound to be more sensitive.
On a side note, it is interesting how solvent toxicity is species-dependent: EtOAc, dichloroethane and cyclohexane are much more toxic to insects than to humans.