Distronic explosive

Distronic explosives were a powerful but unstable weapon, used on many worlds as a component in explosive warheads attached to missiles.

The explosives were highly dangerous, even before they were detonated, causing anyone exposed to unshielded distronics to develop Distronic Toxaemia. In just a short space of time, this disorder causes fatigue and then kills the victim. (DW: Genesis of the Daleks) As distronic explosive decays it becomes unstable and when subsequently exposed to sunlight, it is prone to spontaneous detonation. Because of this instability, distronic explosive was at one point banned throughout the galaxy. (DWAM: Smart Bombs)

Appearances
Towards the end of the Thousand Year War on Skaro, the Thals developed a rocket with a distronic warhead. To load this explosive onto the rocket they used captured prisoners, including Sarah Jane Smith and Sevrin, as expendable slave labour. Rather than die from distronic toxaemia, the workers attempted an escape from the Thal dome which ultimately failed. The rocket was used later to destroy the Kaled city. (DW: Genesis of the Daleks)

The Tenth Doctor and Rose later met a group of sentient missiles whose warheads were packed with distronic explosive. Because of the explosive's instability to sunlight, the missiles could not venture onto the surface of their planet until another missile exploded, causing a nuclear winter which blocked out the sun and allowed the missiles to go out and play on the surface. (DWAM: Smart Bombs)
 * It is not made clear in Smart Bombs exactly when distronics were banned or in which galaxy.