Thalaron

From FEInfobase

Thalaron radiation is a hazerdous radiation Its danger is such that a microsopic amount could kill everyone on board a starship or devestate a planet. It turns all organic matter into an extremely unstable and rocklike substance on contact that is also noticeably brittle.

Thalaron radiation was the key weapon aboard the Reman Warbird, known as the Scimitar, which was intended to eliminate the population of Earth. However, it is apparently extremely volatile, as a simple phaser shot into its generator on the Scimitar was enough to detonate it, completely destroying the Scimitar. The Thalaron radiation needs very much time to get ready, but if its ready, it has a destructive function. It can destroy everything in its range.

Because of its hazards, thalaron research is banned by the Federation. Its only known useful purpose is as a weapon, and as such detecting it aboard a ship is almost certainly a sign of ill intentions