Krypton (Kr) is a colorless gas that occurs naturally in the air. Krypton-85 can be both naturally-occuring and man-made. It is generally used for leak detection and spark gaps.
Krypton-85 is a colorless, odorless and tasteless gas that emits low levels of gamma and beta radiations. It is one of the 5 radioisotopes of krypton, and has a half-life of 10.756 years.
Mixtures of Krypton-85, argon and xenon are used to improve the ionization and reduce the voltage in tungsten-filament light bulbs. Krypton-85 is also used in plasma displays, spark gaps, and leak detection systems.
Krypton is a non-toxic asphyxiant that has narcotic effects over the human body. Krypton-85 is highly toxic and may cause cancers, thyroid disease, skin, liver or kidney disorders.