104 STAT. 2654 PUBLIC LAW 101-549—NOV. 15, 1990 preceding reporting period. Each such report shall be signed and attested by a responsible officer. No such report shall be required from a person after April 1 of the calendar year after such person permanently ceases production, importation, and exportation of the substance and so notifies the Administrator in writing. "(c) BASELINE REPORTS FOR CLASS I SUBSTANCES.— Unless such information has previously been reported to the Administrator, on the date on which the first report under subsection (b) is required to be filed, each person who produced, imported, or exported a class I substance (other than a substance added to the list of class I substances after the publication of the initial list of such substances under this section) shall file a report with the Administrator setting forth the amount of such substance that such person produced, imported, and exported during the baseline year. In the case of a substance added to the list of class I substances after publication of the initial list of such substances under this section, the regulations shall require that each person who produced, imported, or exported such substance shall file a report with the Administrator within 180 days after the date on which such substance is added to the list, setting forth the amount of the substance that such person produced, imported, and exported in the baseline year. " (d) MONITORING AND REPORTS TO CONGRESS. —(1) The Administrator shall monitor and, not less often than every 3 years following enactment of the Clean Air Act Amendments of 1990, submit a report to Congress on the production, use and consumption of class I and class II substances. Such report shall include data on domestic production, use and consumption, and an estimate of worldwide production, use and consumption of such substances. Not less frequently than every 6 years the Administrator shall report to Congress on the environmental and economic effects of any stratospheric ozone depletion. "(2) The Administrators of the National Aeronautics and Space Administration and the National Oceanic and Atmospheric Administration shall monitor, and not less often than every 3 years following enactment of the Clean Air Act Amendments of 1990, submit a report to Congress on the current average tropospheric concentration of chlorine and bromine and on the level of stratospheric ozone depletion. Such reports shall include updated projections of— "(A) peak chlorine loading; "(B) the rate at which the atmospheric abundance of chlorine is projected to decrease after the year 2000; and "(C) the date by which the atmospheric abundance of chlorine is projected to return to a level of two parts per billion. Such updated projections shall be made on the basis of current international and domestic controls on substances covered by this title as well as on the basis of such controls supplemented by a year 2000 global phase out of all halocarbon emissions (the base case). It is the purpose of the Congress through the provisions of this section to monitor closely the production and consumption of class II substances to assure that the production and consumption of such substances will not: "(i) increase significantly the peak chlorine loading that is projected to occur under the base case established for purposes of this section;
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