You can start by the looking at the EU Chemical database (echa.europa.eu) since EMIM OAC is REACH registered, all sorts of tox tests have been made. Hydrolysis of the anion in water is not very probable, since the products that would be obtained are an acid and a base, that would immediately react back to the acetate ( yes, the acid is not a strong one, so some sort of equilibrium is of course present). By the way, the pH of a diluted EMIM OAc solution is about 8-9, depending of course on how it was made, what impurities it contains and so on.
it really does depend how you define toxicity and towards what. There is no evidence that EMIM OAc is toxic (acute oral or dermal) to humans or rats, it does of course depends on the purity (eg. excess of imidazoles or acetic acid).