The bright red exit signs that direct people to exits in commercial buildings are manufactured with a radioactive gas that allows them to glow in the dark, even if the power goes out. This radioactive gas called tritium needs to be properly disposed of because it can cause serious contamination. All tritium exit signs are clearly labeled with a yellow label, red print, and a radioactive symbol. These labels include the make, model, serial number, manufacturing date, and expiration date. This information will be required when you dispose of a tritium exit sign for recycling.