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I'm confused about aerosol sprays. They have been labeled one of the worst enemies of the ozone layer, producing nasty destructive chemicals by the truckload, and yet there are now aerosol cans that specifically say "environmentally safe." How can this be? Are there different kinds of propellants used? Two related questions: Why can't aerosol products be produced in a simple pump-spray version, and can you recycle aerosol cans like other cans? --Larry Axelrod, Chicago

I don't want you to feel like you're completely out of it, Larry--I am always solicitous of the Teeming Millions' feelings--but the ozone-destroying chemicals in aerosols (chlorofluorocarbons, or CFCs) were banned in 1978. Today propellants like propane, nitrogen, and carbon dioxide are used instead. If it's any comfort, a lot of people are under the same misimpression you are. CFCs are still used in things like auto air conditioners, but they're supposed to be totally phased out by 1995.

As for whether aerosols are environmentally safe in general . . . well, I guess it's all a matter of definition. Some aerosols are (or were) safe except for the portion of the environment that you personally happen to be in. Until the late 1980s, for example, some hair sprays used methylene chloride as a solvent/propellant/flame retardant. The drawback of methylene chloride was that it was allegedly carcinogenic. The use of this chemical has now been banned as well.

As for your other questions: (1) Some aerosol products can be reformulated for pump-spray use but not all--shaving cream and silicone sprays, for example. In addition, aerosols can't be tampered with, they're guaranteed sterile, they make the most effective asthma inhalers, etc. (2) Aerosol cans can be recycled. Studies have shown that most aerosol cans are empty (i.e., depressurized) when discarded and thus present no danger. But even if the aerosol cans are still partly pressurized when they're crushed during the recycling process, they're surrounded by ordinary cans inside a heavy steel baling machine. The Steel Can Recycling Institute says no incidents have been reported by any of the 300 recycling operations now accepting aerosol cans. Recycle away.

Advances on the Anti-Boom-Box Front

Your recent column about using EMP [electromagnetic pulse] to combat "boom cars" [February 26] shows real forward thinking. Your tax dollars are already being applied to this problem. Federal scientists have the fix at hand. Once again, you are both ahead of and behind the curve. --Rob Mohr, Chicago

It's a gift, babe. You enclose an article from Aviation Week reporting that the Air Force, sensitive to the boom car phenomenon but reluctant to use nuclear weapons to combat it, is developing a new weapon that will generate EMP by nonnuclear means. "A nonnuclear EMP burst is produced by creating a magnetic field in a coil and then squeezing it by the detonation of conventional explosives," it says here. "The resulting pulse of microwave energy can carry thousands of feet and damage or upset electronic components."

The Air Force is retrofitting a bunch of ex-nuclear cruise missiles with the EMP generators. We know they'll work, too. Aviation Week continues, "In early 1993, private automobiles parked about 300 meters from a U.S. EMP generator test site had their coils, alternators, electric seats and electronic engine controls accidentally disabled by the pulse." Accidentally, eh? Sure. I say some schmuck in a Toyota played one rap song too many.

Some Insight on the Origin of the Conflict in Bosnia-Herzegovina

As a Welsh American, I am deeply offended by your use of the ethnic slur "welshed" [December 25]. What is your factual basis for stereotyping Welsh people as a race who fail to honor their obligations? You owe the people of Wales an immediate apology. --Malcolm Solomon, Palo Alto, California

OK, I apologize. Next time I'll say they "malcolmed" on the deal.

Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.


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