Mercury is a naturally occurring element found in rocks, soil, water, air, and living things. It can also be found in certain products. Mercury is a neurotoxin and negatively affects a person’s health based on how you are exposed (breathing, eating, skin contact, etc.), how long the exposure lasts (amount and duration of exposure), age of the person exposed (younger children still developing are most vulnerable) and the form of mercury (elemental/metallic mercury as a shiny, silver-white, odorless liquid or methyl mercury through food like fish).