Chlorofluorocarbons Are Banned in the United States

Date March 17, 1978

The U.S. Consumer Product Safety Commission, Environmental Protection Agency, and Food and Drug Administration banned chlorofluorocarbons in aerosol sprays because these chemicals are harmful to Earth’s protective ozone layer. This step increased the willingness of other nations to discuss the ozone problem productively and on a continuing basis.

Locale Washington, D.C.

Key Figures

• S. John Byington (fl. late twentieth century), chairman of the Consumer Product Safety Commission
• Douglas M. Costle (fl. late twentieth century), administrator of the Environmental Protection Agency
• Donald Kennedy (b. 1931), commissioner of the Food and Drug Administration
• Sydney Chapman (1888-1970), mathematician, geophysicist, and astronomer
• F. Sherwood Rowland (b. 1927), professor of chemistry at the University of California, Irvine
• Mario J. Molina (b. 1943), professor of chemistry at the University of California, Irvine

Summary of Event

A joint ban on the nonessential use of chlorofluorocarbons in aerosol sprays was announced on March 17, 1978, by the U.S. Consumer Product Safety Commission (CPSC), the Environmental Protection Agency (EPA), and the Food and Drug Administration (FDA). At the time, chlorofluorocarbons were used in approximately 97 percent of all aerosol sprays. The ban was engineered to take effect in three phases: On October 15, 1978, production of chlorofluorocarbons for use in aerosols ended; on December 15, 1978, most chlorofluorocarbon aerosol manufacture ended; and on April 15, 1979, a ban of interstate shipment of aerosols took effect. The small percentage of aerosols allowed to remain in use included those used in inhaled respiratory medications and in certain aircraft maintenance products. FDA commissioner Donald Kennedy, EPA administrator Douglas M. Costle, and CPSC chairman S. John Byington praised the chlorofluorocarbon ban as a model for future interagency cooperation; they also referred to its utility, its timeliness, and the avoidance of any hardships to the consumer.

The ban resulted from concerns raised by several major consumer organizations in the early 1970’s and from a 1976 National Academy of Science report that chlorofluorocarbons, particularly the widely used compounds Freon 11 and Freon 12 released into the atmosphere from aerosol and industrial use, could be the main cause of observed stratospheric ozone depletion. The work of F. Sherwood Rowland and Mario J. Molina, chemistry professors at the University of California, Irvine, was particularly important in the realization that chlorofluorocarbons could deplete ozone, which could in turn lead to greatly elevated ultraviolet light levels reaching Earth’s surface. Such an increase was thought to be capable of seriously elevating the incidence of human skin cancer, adversely altering agricultural yields, and changing the global climate.

Chlorofluorocarbons, which are often referred to by the trademarked name Freons, were invented by Du Pont Corporation chemists in the 1930’s. They are gases at room temperature containing the three elements chlorine, fluorine, and carbon, hence their often-used three-letter acronym, CFC. All CFCs are inert materials; under normal conditions near Earth’s surface they do not burn, dissolve in solvents to form solutions, or react with any other substances. For these reasons, CFCs proved ideal for use in aerosol sprays (for example, deodorants and hair sprays); even after the ban, they continued to be used widely as air-conditioning coolants, as refrigerants, and in the production of foamed plastics and other foams. In 1977, 50 percent of all CFCs made in the United States were used in aerosol sprays.

The danger of CFCs is that their property of inertness applies only at ground level. When CFCs rise into the upper atmosphere, a very small amount of ultraviolet light breaks them down into substances that destroy large amounts of ozone. Computer models in the 1970’s supported the hypothesis that the effect of this process on the stratospheric ozone content could be severe.

The stratospheric ozone layer is important to life on Earth. Sunlight is composed of electromagnetic radiations, some of which fall into the very high energy ultraviolet range that causes skin tanning and sunburns. This light can also penetrate living tissues and damage or kill them, and in humans, it can cause skin cancer. In fact, ultraviolet light is considered a major cause of such cancers.

The ozone layer provides protection from the dangerous effects of ultraviolet light by filtering out this part of the sunlight. Thus, any substance that decreases the amount of ozone in the upper atmosphere is a potential danger, a danger all the greater because there is so little ozone in the atmosphere (less than one millionth of the amount of nitrogen).

Ultraviolet light damages not only humans but also green plants, including food crops, and other animals. Ultraviolet damage to the microscopic plankton in the oceans, for example, could alter deep-sea ecology and food production as well as world oxygen production, since plankton are a major part of the food base for other organisms and important oxygen producers. Moreover, because ultraviolet light is energy, an increase of light in the lower atmosphere will warm it, if only by a few degrees. This warming, in conjunction with the damage to plants and plankton, could lead to changes in the global climate.

Ozone (O³) is a relatively rare and somewhat unstable form of oxygen, produced when three oxygen atoms combine. It is in constant flux with regular oxygen (O²); as one molecule of ozone forms, another reverts to oxygen. Normally, equilibrium exists between the breakdown and formation of O³ that keeps it at appropriate levels; this process, identified by British geophysicist Sydney Chapman in 1929, is called the Chapman cycle.

CFCs upset the Chapman cycle when they enter the stratosphere and the ultraviolet light breaks them down into their components. Each chlorine atom can then destroy hundreds to thousands of ozone molecules. It is this property that makes the CFCs potentially so dangerous. Moreover, their relative stability in the lower atmosphere, where they can exist unchanged for one hundred years or more, makes CFCs a long-term threat. Legislated reduction of CFC production has prevented harm from new ozone depleters, but it cannot undo the damage caused by the CFCs already released. That damage is ongoing, but it is also reparable. With the depletion and then prohibiton of CFC usage that has occurred at the national and international levels, the ozone layer is expected to regenerate itself by natural means sometime around the middle of the twenty-first century.

Significance

The furor over CFCs and ozone had a great impact on Western society; some responses had almost immediate results, whereas others may take decades to interpret and quantify. Even before the CFC ban, public opinion—in the form of consumer choice—had led to an estimated 38 to 41 percent drop in the yearly release of aerosol between 1973 and 1977. Many hailed this as a positive consequence of the public discussion of the subject.

CFC use in the United States, however, represented only about 15 percent of the total world use. To make the ban truly effective, the rest of the CFC-producing and CFC-using nations would need to cooperate as well. Canada, Denmark, and Sweden soon enacted similar legislation, in part as a result of meetings organized by the United Nations Environment Program and the EPA that brought together scientists and statesmen from the major CFC-producing nations of the world. It was considered encouraging that the various nations were willing to discuss the problem productively and on a continuing basis. The drafting of the Montreal Protocol in 1987 and its subsequent amendments in 1990 and 1992 eventually called for the discontinuation of production of CFCs. Additional revisions of the treaty were undertaken in later years as international scrutiny of the issue continued. Stabilization or reversal of ozone depletion was realized, causing many to hail the Montreal Protocol as the most successful international environmental agreement ever promulgated.

Another consequence of the diminution of CFC aerosol use was the worldwide search for new chemicals to be used in their place, with simultaneous examination of potential ozone-depleting effects. Many possible replacements were found to exist, including pump dispensers that require only air to form aerosols, simple hydrocarbons, dry powders, and other halogenated chemicals related to CFCs but lacking or containing low amounts of chlorine. All have advantages and disadvantages. Many chemical CFC substitutes were found to share the ability to deplete the ozone layer. Study of halons—close cousins of the CFCs used in firefighting foams—showed that they, too, are ozone depleters.

One of the dilemmas associated with finding replacements for CFCs is that nothing can be definitely identified as “ozone-friendly” without a testing period of a decade or longer. At the same time, the chemicals to be tested must be proven to be safe for consumers. That requirement limits their chemical composition to substances that are neither toxic nor flammable, and while flammability is easily tested, toxicity testing requires considerable time. However, progress in halting ozone depletion suggests for now that many of these concerns were overemphasized, and that optimism for improvement is justified.

Bibliography

Benedick, Richard Elliot. Ozone Diplomacy: New Directions in Safeguarding the Planet. Rev. ed. Cambridge, Mass.: Harvard University Press, 1998. The definitive book about the Montreal Protocol. The author was the chief U.S. negotiator of the 1987 treaty.

Bernards, Neil, ed. The Environmental Crisis: Opposing Viewpoints. San Diego, Calif.: Greenhaven Press, 1991. Provocative collection of essays on environmental topics from widely differing viewpoints. Contains several discussions of the CFC-ozone problem. Equally important are the thoughtful commentaries on the roles of the government, the public, and the activist in the solution of such problems.

Hillary, Sir Edmund. Ecology 2000. New York: Beaufort Books, 1984. Contains useful information on the stratospheric ozone problem and on CFCs. Also examines other problems that may arise from ozone depleters or their removal from the atmosphere.

Panofsky, Hans A. “The Earth’s Endangered Ozone.” Environment 120 (April, 1978): 16-20, 40. Good, objective overview. Discusses in detail but in simple terms the ozone layer, its perpetuation, and its destruction by human-made chemicals, such as chlorofluorocarbons.

Parson, Edward A. Protecting the Ozone Layer: Science and Strategy. New York: Oxford University Press, 2003. A highly detailed history of international efforts to protect the ozone layer since the 1970’s.

Roan, Sharon L. Ozone Crisis: The Fifteen-Year Evolution of a Sudden Global Emergency. New York: John Wiley & Sons, 1989. In-depth history of the CFC-ozone problem. Includes information on the chemistry of ozone and related materials and discusses potential consequences, solutions, and alternatives to the use of CFCs.

Snyder, Carl H. The Extraordinary Chemistry of Ordinary Things. 4th ed. Hoboken, N.J.: John Wiley & Sons, 2003. Chemistry text for the nonscientist that covers the basic chemistry needed to evaluate the problems associated with CFC effects on ozone. Includes a useful section on the topic.