Medical supply kit
This item is similar in appearance to a doctor's bag. However, it is contaminated. With 35 Medicine, you can sterilize it with 1 bottle of either whiskey, scotch, or vodka (all of which can be found in a nearby fridge). Otherwise, you can replace the contaminated parts with 1 bottle of turpentine and 1 roll of duct tape, salvage it, or take it with you and sterilize it at a campfire. Note that salvaging the parts will give you less XP for the quest Tourist Trap than the other options.
It can be found on a table located in the back area of Zion Ranger station.