It was oil companies like Halliburton that first developed the technique of fracing, (pronounced fracking) or fracturing coal beds to release the methane that was bound to the surface of the coal. In the fracing process, a toxic brew of chemicals which may include diesel fuel, benzene, propylene glycol, napthalene, aromatics, etc., are pressure-injected along with explosives to break up and force millions of fissures throughout the coal bed.