How can bases harm you?
Hydroxides can cause severe burns and tissue damage, but there is an added hazard.
If you spill acid on your skin, you know it immediately. It burns, and you wash it off. On the other hand, if you spill base on yourself, the reaction is not so immediate. It still causes tissue damage, but because it does not hurt so much, you don't notice it, and the longer your skin is in contact with it, the more damage it does.
Chemists typically use large alcoholic base baths to clean glassware from grease and oil. Of course eye protection and long gloves would be worn, but if the gloves have a hole in them (all too possible), your hands are in contact with the base while you are unaware of the exposure. The glassware is transferred from the base bath to the acid bath (after a rinse in running water). It is in the acid bath you notice that there is a hole in the gloves: it stings like buggery. And when this occurs you change the gloves....