A bill to amend the Clean Air Act to provide for further assessment of the validity of the theory concerning depletion of ozone in the stratosphere by halocarbon compounds before proceeding with any further regulation of such compounds, to provide for needed further research and study, and for other purposes.

Amends the Clean Air Act to revise provisions for ozone protection.

Directs the Administrator of the Environmental Protection Agency to give priority in ozone protection studies and research to increasing actual measurements of stratospheric ozone and improving methods of identifying potential trends in such measurements.

Directs the Administrator to contract annually with the National Academy of Sciences to: (1) continue review and research; (2) determine the extent, nature, and causes of changes in stratospheric ozone concentration; (3) investigate probable or possible effects on health and the environment; and (4) report all findings and associated uncertainties.

Directs the National Academy of Sciences, in consultation with the National Aeronautics and Space Administration and the Administrator of the National Oceanic and Atmospheric Administration, to report, within two years after enactment of this Act and annually thereafter, all findings concerning actual or potential alteration of the concentration of ozone in the stratosphere, its causes, and associated implications and uncertainties. Requires that such report be made to the Administrator and to the Congress, with copies available to the public.

Requires that research and monitoring programs be continued and expanded to determine the extent, nature, causes, effects, and associated uncertainties of stratospheric ozone changes.

Directs the President, within two years after enactment of this Act and annually thereafter, to report to the Congress and the public on efforts to reach international agreements among the major free-world producing countries of chlorofluorocarbons as to the nature, extent, and implications of any threat to the concentration of ozone in the stratosphere and as to the appropriate regulatory action to be taken.

Directs the Administrator, in proposing further regulations for the control in the United States of any chlorofluorocarbon under the Act or the Toxic Substance Control Act, to first: (1) determine that chlorofluorocarbons are contributing to depletion of the stratospheric ozone which is occurring, or is likely to occur, at a rate that may reasonably be anticipated to endanger the public health or welfare; or (2) report that international agreement has been reached as to the nature, extent, and implications of any threat to the concentration of ozone in the stratosphere and as to the appropriate regulatory action to be taken. Directs the Administrator, in promulgating such regulations to: (1) take into account any unresolved scientific questions and the availability of suitable alternative products; and (2) specifically consider the health implications of chlorofluorocarbon chemical substitutes and implications of ozone depletion for the public health and welfare.