Toxicological and hygienic evaluations were made of the wastes produced by aluminum-making plants and thermal power stations in the Krasnoyarsk Territory, which confirmed for the first time the environmental toxicity of ash-dump waste, derived from slicing and dusty burning of brown coals from the Kansk-Achinsk field, and nepheline slurries resulted from the processing of urthites from the Kiy-Shaltyr deposit to prepare alumina. They were found to exert a toxic effect on warm-blooded animals, to have cyto- and phytotoxicity and mutagenic activity in the Ames test. Class III hazard was established for slurries of aluminum making (nepheline and gas purifications) and Class IV hazard for ash-dump waste and coal foam flotation tailings. The study has yielded data on the high level of natural radionuclides (as high as 2 kBq/kg) in the ash slurries from in the Berezovsk brown coal field, which requires that the procedure for their controlling and handling should be determined.