Aerosol sprays: Timing the phaseout

The conclusions of the long-awaited report from the National Academy of Sciences were straightforward: In the long run the use of fluorocarbons in aerosol sprays will probably have to be cut back, but there is no imminent danger requiring immediate government regulation. If some restrictions must eventually be imposed, a delay of two years while additional information is gathered would not have serious repercussions.

Yet within a month after these conclusions were reported in September 1976, federal agencies began to announce plans to phase out the use of these chlorofluoromethanes (or CFMs as they are called in the academy report, or fluorocarbons as they have more commonly been described).

First of all the Food and Drug Administration proposed a ban on propellants containing fluorocarbons used in aerosol hair sprays, deodorants, and antiperspirants and proposed that warning labels be placed on existing stocks. Then, the Environmental Protection Agency confirmed that it would institute a phaseout of non-essential fluorocarbons under its jurisdiction (primarily in pesticides). In addition, it would require labeling of all products containing fluorocarbons produced or leased for shipment after April 15, 1977. Finally, the Consumer Product Safety Commission granted a petition by the National Resources Defense Council on November 24, 1976 requesting promulgation of safety standards that would ban fluorocarbon sprays in such items as household cleaners.

Most European countries and Japan on the other hand, are taking are taking a more cautious attitude toward any possible regulation of fluorocarbons.

What is the basis of actions taken by U.S. government agencies and what accounts for the go-slow attitude reflected in the academy report?

The ozone depletion theory. The fluorocarbon controversy came to light in a 1974 article by F. Sherwood Rowland and Mario Molina reporting that the release of fluorocarbons could harm the earth's ozone layer. They found that ultraviolet rays split fluorocarbon molecules, forming chlorine and other compounds. The chlorine, in turn, attacks ozone in a chain reaction: every molecule of chlorine knocks out approximately 10,000 molecules of ozone thereby depleting the concentration of ozone. Based almost entirely on laboratory experimentation and computer projections, Rowland and Molina estimated that the continued release of fluorocarbons into the atmosphere would deplete the earth's ozone layer by between 7 and 13 percent in 15 years.

Results of intensive research in the two years since Rowland and Molina's predictions have been essentially in agreement with the earlier findings. Thus the academy report concluded that continued release of fluorocarbons at a rate corresponding to their use in 1973 would eventually cause between 2 and 20 percent reduction in stratospheric ozone, the best estimate being about 7 percent. The rate of reduction would initially be about 0.1 percent a year, reaching 3.5 percent after 50 years.

Effects on skin cancers and climate. The small amount of ozone in the stratosphere (one part in four million) absorbs virtually all solar ultraviolet radiation in the range that is biologically harmful. As a consequence, the depletion of ozone would cause more biologically active ultraviolet rays to reach the earth's surface. The major effects could be: (1) increased incidence of malignant melanoma, a serious skin cancer, frequently causing death; (2) increased incidence of less serious, but more prevalent forms of skin cancer rarely causing death; and (3) adverse effects of unknown magnitude on plants and animals.

A second danger is the possibility that the accumulation of fluorocarbons in the atmosphere would absorb infrared radiation emitted from the earth and prevent it from radiating into space, thereby warming the atmosphere (a so-called greenhouse effect). The most important impact of such a climatic change would be on agriculture, particularly on the boundary areas where certain crops could grow. However, even assuming an increase in mean global temperature of 0.5 degrees Celsius (0.9 degrees Fahrenheit) from this cause, the academy report concluded that the effects of this change on crop yields and natural ecosystems would probably be of little consequence except in areas of marginal crop production.

Despite the studies that essentially agree with Rowland and Molina, considerable uncertainty remains. One reason for this uncertainty involves yet unknown chemical reactions in the atmosphere. Another concerns the fact that ozone damage is predicated on the assumption that there are no significant tropospheric "sinks" that would reduce the quantity of fluorocarbons interacting with ozone in the stratosphere. A third uncertainty involves the inadequacies of existing models to analyze atmospheric behavior.

To put it simply, no observable data have yet confirmed a decrease (or increase) in the global stratospheric ozone, whether or not due to fluoro-carbon releases. This is hardly surprising since a 0.5 percent reduction—that estimated to have already been produced by past releases of fluorocarbons—is not detectable because natural fluctuations can be plus or minus 5 percent.

With these factors in mind, the academy committee concluded that it would not be feasible to measure the precise extent of ozone reduction in the stratosphere for several years. In addition, it found that while advances in predicting climatic effects could be expected over the next several years, the climatic impact of fluorocarbon releases would remain even less precise. However, it did believe that assessments could be significantly improved during the next two years because of better stratospheric and atmospheric laboratory measurements. These improved measurements could provide a better basis for government policy.
Thus, given the high degree of uncertainty surrounding the ultimate effects of continued CFM release, the question still to be addressed is: what are the economic gains and potential losses from delaying the decision to ban CFM-propellant aerosols?

Gains and losses from delay. Worldwide uses and releases of fluorocarbons had been growing by about 10 percent a year through 1974, but because of adverse publicity, they decreased from 1974 to 1975 by about 15 percent and continued to decrease in 1976. All of the 1975 decrease took place in the United States, which accounts for about half the total use. Various uses of CFMs have very different impacts on human welfare and also release significantly different amounts into the atmosphere. For example, home refrigeration is important to human health and presently accounts for less than 1 percent of worldwide releases, whereas such non-essential sprays as those dispensing antiperspirants, deodorants, and hair care products account for over half of the worldwide releases.

From these figures, one might conclude that an immediate ban on aerosols containing fluorocarbons is justified, but there are a number of very clear advantages of aerosols propelled by fluorocarbons. First, they have boiling points well below room temperature and the content's pressure remains relatively constant throughout use. This results in consistent aerosol particle size, spray pattern, and throw. Second, they produce a very fine dispersion of the active ingredient. Third, they are odorless and stainless. Fourth, they are nonflammable even in blends with significant concentrations of flammable solvents. Fifth, they enjoy one of the least toxic ratings for any chemical. Sixth, they are unusually inert and have a long shelf life.

Alternative propellants have a number of drawbacks. For example, hydrocarbon propellants have many of the same characteristics and are less costly, but they are highly flammable. Compressed gases such as nitrogen, nitrous oxide, or carbon dioxide lose propellant pressure as the active ingredient is consumed. Mechanical spray pumps cannot easily achieve uniform dispersion of tiny spray particles. Thus, the substitution of other propellants or dispensing techniques would be accompanied by a loss of convenience, efficiency, and possibly safety to the consumer.

What would be the costs associated with the two-year delay suggested by the report? The academy committee specifically addressed this question. Basing its conclusions on an ultimate ozone reduction of 7 percent, it calculated that if fluorocarbon use and release were reduced 50 percent in 1979 rather than in 1977 the delay would alter the ozone reduction at any later date by no more than one-sixth of 1 percent. The estimated health effects of delay are extremely small—perhaps fewer than five deaths per year after more than 100 years.

With regard to climatic effects, the academy found that whether a halving of fluorocarbon use and release were to take place in 1977 or 1979, the total amount of fluorocarbons in the atmo-sphere would be altered by no more than 10 percent of the amount now present—an amount whose climatic effects are "probably undetectably small." Finally, the Academy report concluded: "Selective regulation of CFM uses and releases is almost certain to be necessary at some time and to some degree of completeness. Neither the needed timing nor the needed severity can be reasonably specified today. Costs of delay in decision are small, not more than a fraction of a percent change in ozone depletion for a couple of years' delay. Measurement programs now under way promise to reduce our uncertainties quite considerably in the near future."