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 Substances Control Act of 1976 new chemical not listed in the 1976 act by using a PMN. Section 5 of the Toxic Substances Control Act (TSCA) does not require any toxicity testing before submitting a PMN No safety information is required to be included in the PMN, so the EPA must rely on computer modeling to determine whether the new chemical "may present an unreasonable risk." In order to regulate new chemicals, the EPA must determine that the chemical "...may present an unreasonable risk to human health or the environment..." or show that the chemical "... is or will be produced in substantial quantities, and