studied the leachability of heavy metals and major anions from Jordanian El-Lajjun spent oil shale after combustion and they reported that the level of heavy metals increases as the temperature of the ashing process increases. Based on their study, no significant metal release from the ashed Oil Shale has reported. Compared with the EPA limits for drinking water, El-Lajjun Oil Shale ash has low concentrations of trace elements