Period 6 element devices though concerns about the element's toxicity have led to mercury thermometers and sphygmomanometers being largely phased out in clinical environments in favor of alcohol-filled, galinstan-filled, digital, or thermistor-based instruments. It remains in use in scientific research applications and in amalgam material for dental restoration. It is used in lighting: electricity passed through mercury vapor in a phosphor tube produces short-wave ultraviolet light which then causes the phosphor to fluoresce, making visible light. Thallium is a chemical element with the symbol Tl and atomic number 81. This soft gray other metal resembles tin but discolors when exposed to air. The
Toxic waste an impermeable clay cap. Waste transporters and waste facilities may charge fees; consequently, improper methods of disposal may be used to avoid paying these fees. Where the handling of toxic waste is regulated, the improper disposal of toxic waste may be punishable by fines or prison terms. Burial sites for toxic waste and other contaminated brownfield land may eventually be used as greenspace or redeveloped for commercial or industrial use. RCRA governs the generation, transportation, treatment, storage, and disposal of hazardous waste. The Toxic Substances Control Act, also enacted in 1976, authorizes EPA to collect information on all new and