Mercury is a naturally-occurring chemical that exists in several forms, metallic (elemental), organic and inorganic. Most health concerns focus on methylmercury in fish, and on metallic mercury, which has been used in many products in the past. Elemental mercury is a shiny, silver-gray liquid metal that scatters into droplets when spilled. At room temperature, liquid mercury will vaporize (evaporate) into air. Mercury vapor cannot be seen or smelled. Common items containing elemental mercury include: thermometers, thermostats, blood pressure units, barometers, gas pressure regulators, florescent light bulbs, and antiques.