Chronitons are subatomic particles with temporal properties. Although not harmful to humanoids, chronitons can be fatal to lifeforms which exist outside of time, such as the beings known to the Bajorans as "Prophets," and their mortal enemies, the Pah-wraiths.
Chronitons were produced by the normal operation of Romulan cloaking devices, and were often associated with the phenomenon of time travel. The Orb of Time was known to produce a surge of chronitons when in operation.
- Chroniton Particles on Memory Alpha