Uranium in the environment resulting in workers exposed to high levels of radiation. Conventional uranium ore treatment mills create radioactive waste in the form of tailings, which contain uranium, radium, and polonium. Consequently, uranium mining results in "the unavoidable radioactive contamination of the environment by solid, liquid and gaseous wastes". Inhalation of radon gas caused sharp increases in lung cancers among underground uranium miners employed in the 1940s and 1950s. In the 1940s and 1950s, uranium mill tailings were released with impunity into water sources, and the radium leached from these tailings contaminated thousands of miles of the Colorado River system. Between 1966 and
Uranium poisoning in Punjab early as 1995, Guru Nanak Dev University (GNDU) released a report, showing the presence of uranium and other heavy metals beyond permissible limits in water samples collected from Bathinda and Amritsar district, however there was no response from the government at that time. The hotspot for this increased toxicity, however was the Malwa region of Punjab, which showed extremely high levels of chemical, biological and radioactive toxicity, including uranium contamination. As the region's groundwater and food chain was gradually contaminated by industrial effluents flowing into fresh water sources used both for irrigation and drinking purposes, the region showed a rise