Lewisite

At concns below /at which one can detect the material by smell/, it is irritating to the eyes & mucous membranes.

If ocular exposure occurs, they cause immediate pain, blepharospasm, & rapid formation of eyelid edema. ... Immediate pain upon skin contact. A skin contact of only 5 min will cause a chemical burn that results in a deep ulceration. Lewisite may also cause somewhat more nasal irritation than mustard gases.