Satellites back up theory that sprays hurt ozone

Two satellites have produced the first experimental evidence backing the theory that gases once used in spray cans may be eroding the ozone layer shielding the earth from harmful radiation.

The space agency scientist analyzing the data said it is impossible to pin the blame on fluorocarbon gases -- now banned in spray can products -- or even to determine whether the overall ozone shield is being damaged. He said questions have been raised because instruments in both spacecraft show that ozone is being depleted at the altitude of 25 miles, which corresponds to the theory that a chemical reaction triggered by fluorocarbons has its greatest effect at 25 miles.