Unless you're going to inhale or injest the Mitomycin C, I think it's safe to use. You're wearing a surgical gown, gloves, mask, and head cover. If using Weck cells soaked in MMC to apply it to the eye, then you really don't get it all over you. It only touches the instruments, patient's eye, and Weck cells. You also rinse copiously with water.
I think it's safe if you use standard surgical precautions.