EPA is promulgating a significant new use rule (SNUR) under section 5(a)(2) of the Toxic Substances Control Act (TSCA) for elemental mercury (CAS No. 7439-97-6) for use in flow meters, natural gas manometers, and pyrometers, except for use in these articles when they are in service as of September 11, 2009. This action will require persons who intend to manufacture (including import) or process elemental mercury for an activity that is designated as a significant new use by this rule to notify EPA at least 90 days before commencing that activity. Persons subject to the provisions of this rule will not be exempt from significant new use reporting if they import into the United States or process elemental mercury as part of an article. The required notification will provide EPA with the opportunity to evaluate the intended use and, if necessary, to prohibit or limit that activity before it occurs.