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Saving the atmosphere takes on urgency

If you're feeling slightly persecuted about having to spend more on fixing the car's air conditioner, take heart: You are not alone. Millions of products and processes are being changed out of consideration for the ozone layer.

Chlorofluorocarbons, which have been around since the 1930s, were first used in refrigerators, then air conditioning. Before long, they branched out to aerosol spray propellants, solvents used to manufacture electronics, blowing agents for plastics and foam for packaging and insulation.

Here's the problem: When CFCs drift up into the atmosphere, ultraviolet radiation bombards the CFC molecule, setting off chemical reactions that destroy ozone. Researchers have linked the diminishing ozone layer with increased incidence of skin cancer, cataracts and other serious ailments.

But even if production of all CFCs and other ozone-depleting chemicals were to stop immediately, scientists say there's already enough of the material in the atmosphere to keep destroying the ozone layer well into the 21st century.

So it isn't hard to understand the urgent need to find replacements.

Some of the work is being done locally, at the Center for Applied Engineering in St. Petersburg. There, researchers developed some of the formulations that are being used for a new blowing agent to make foam insulation, used primarily in commercial roofs, said vice president Lorraine M. Aulisio.

Finding a substitute is just one part of the job.

"The reason we didn't switch (to the new formulation) sooner was that there was no substitute sitting there," Aulisio said. "The chemical manufacturers knew of some, but they hadn't gone through all the testing."

When you consider the hundreds of products that use ozone-depleting chemicals, it isn't hard to understand why the conversion is so time-consuming.

"You need animal exposure tests, acute toxicity tests, not to mention finding ways of making the manufacturing process efficient so it doesn't end up costing a zillion dollars a pound," Aulisio said.

According to the U.S. Environmental Protection Agency, there are eight categories of industry that use ozone-depleting chemicals, ranging from cigarettes to sterilizers. The EPA is in the process of approving a long list of acceptable substitutes, some of which will be approved only until something even more environmentally friendly is found.

1. Refrigerants. More than a half-billion pieces of refrigeration and air conditioning equipment use CFCs. These include air conditioners for vehicles and buildings, household refrigerators and freezers, cold storage warehouses and refrigerated trucks.

2. Foams. In 1990, about 18 percent of all ozone-depleting chemicals in the United States were used in the manufacture of foam plastics. The chemicals are used as blowing agents to create bubbles in the plastic foam structure.

3. Industrial cleaning solvents. These constituted about 15 percent of the chemicals slated for phase-out. The electronics industry, for instance, uses CFCs to clean circuit boards during manufacturing. Research is being done on ways to eliminate the cleaning stage from the process, and thus the use of CFCs.

4. Halons. Long favored for their ability to extinguish fires without damaging the property they are protecting, these chemicals are considered the largest sector of ozone-depleting substances. These are used mostly in home and commercial fire extinguishers, but also in automatic "flooding systems" typically used in conjunction with fire detection devices. According to the EPA, halon production comprised just two percent of the ozone-depleting chemicals manufactured in 1986, but they represent 23 percent of the ozone depletion capacity of halons and CFCs combined.

5. Sterilants for medical equipment. CFC-12 _ that's Freon _ is mixed with ethylene oxide, the chemical that actually sterilizes medical devices. But on its own, ethylene oxide is highly flammable. This is a fairly small category of CFC usage _ about 4 percent in 1990.

6. Aerosols. The use of CFCs as an aerosol propellant was banned in 1978 for all but "essential applications" such as certain medications. Before the ban, propellants accounted for 50 percent of all CFC consumption. After the ban, that usage was cut by 95 percent.

7. Tobacco Expansion. This is the process of increasing the volume of tobacco in making cigarettes. One way of doing it is to saturate the tobacco with a CFC in a stainless-steel vat, and then pumping in hot air to expand the tobacco. The CFC is recovered and recycled. The EPA has approved the use of carbon dioxide as a substitute technology, and is considering two proposed types of hydrofluorocarbons in tobacco expansion.

8. Adhesives, Coatings and Inks. Methyl chloroform (MCF), another chemical that affects the stratospheric ozone layer, is used as a solvent in some of these products, favored for its low flammability. Less than a decade ago, many manufacturers switched to methyl chloroform from volatile organic compounds, because the VOCs were considered harmful to the atmosphere at the ground level.