Listen VERY closely.
Dig on the mini-series "Ascension".
NO!
It was the Uranium they couldn't get anywhere near.
Their breathe-gas expolded when near it.
The Psychlos had their home world taken over by a cabal of psychiatrists. (called Catrists).
They had the entire population of their planet under MK and sent them among the stars to mine for any and all resources via the Intergalactic Mining Company.