Letterpress printing involves the use of heavy equipment. Most pieces of equipment were manufactured before OSHA was even thought of. The presses have exposed gears and many pinch points. Paper cutters can cut off hands and fingers. Lead type is heavy. Ink and solvents are flammable. The shop/studio is not the place for wine and weed. Don’t “pop the cork” until the print job is finished, the power is turned off and the mess is cleaned up.
If you have allergies, letterpress printing is not your medium. Ink is solvent based. Clean-up is with kerosene, paint thinner or special roller cleaners. All of these can burn and cause injury to sensitive skin. They do produce “water based” linoleum block ink that can be used with letterpress. You must have rubber rollers and be satisfied with less than perfect work. (After the water based ink dries, it should be sprayed with a fixative to preserve it) I’ve used it in demonstrations with middle-school students. No matter what you have heard, non-petroleum based solvents will not work. They are not strong enough to remove dried ink and they leave a residue.
Type metal contains lead, tin, antimony and copper. Don’t let the lead frighten you. Just wash your hands when you are finished. Just as you would when working with any other medium. Studies have been done with retired printers regarding lead related illnesses. The results were the same as with any other segment of the population. (From what I’ve seen, more printers die from alcohol than any other illness.)
When you buy used type or other equipment, remember, it probably has been exposed to mouse droppings. Wash your hands!