Once a lush tropical swamp, Quesh's atmosphere became toxic after a series of quakes released dangerous chemicals contained below the planet surface. Most of the native wildlife died off, and Quesh became poisonous to virtually all higher species.
Quesh's toxicity is also its source of value‒the chemicals that poisoned the atmosphere are usable in the most powerful adrenals and stimulants. The Republic, with the aid of the Hutt Cartel, has staked a claim to Quesh and is attempting to establish chemical mines. Upon learning of Quesh's existence, the Empire quickly established a presence of its own.