That's what I had always heard, but the Wikipedia article on MEK says that health effects are only linked to very high amounts. Not sure if I should believe Wikipedia, but I suppose some care is always advisable when dealing with chemicals. Acetone, a chemical relative, can cause liver and eye damage; while acetone is not considered terribly toxic, it likely follows that the stronger MEK would do similar if not worse things.

: other folks could correct me but I think it's pretty much at the top of the
: pyramid for dangerous substances to have around.