BERKELEY RESEARCHERS RECEIVE MEDAL OF SCIENCE.

Byline: Associated Press

Two scientists from the University of California at Berkeley have won the prestigious National Medal of Science, the White House and National Science Foundation said.

The recipients are Harold S. Johnston, a pioneer investigator of threat to the ozone layer, and Darleane C. Hoffman, who studies the heaviest elements.

The duo will be among nine scientists honored by President Clinton at a White House ceremony later this year, officials said Wednesday.

UC Berkeley spokesman Robert Sanders has said the medal ``is the United States' equivalent of the Nobel Prize.''

Johnston, now a professor emeritus of chemistry at Berkeley, warned in the 1960s that humans could harm the ozone layer. This chemical layer in the stratosphere shields Earth from cancer-causing radiation.

In 1971, Johnston calculated that nitrogen oxides from supersonic aircraft, or SSTs, might cut ozone levels by close to one-fourth. As a result, he faced intense attack from politicians and industry. The SST was a high priority of then-President Richard Nixon and the U.S. aerospace industry.

Johnston's warnings helped persuade Congress to stop funding the SST program. Later, other scientists showed that pollutants called chlorofluorocarbons also damage the ozone layer.

A native of Woodstock, Ga., Johnston, now 76, retired from UC Berkeley in 1991 and now lives in Kensington with his wife, Mary Ella.

The other winner, Hoffman, 70, is a professor in a UC Berkeley graduate school and works at Lawrence Berkeley National Laboratory. She has studied the heaviest elements, which go by the numbers 104, 105 and 106.

In 1993, Hoffman and other scientists confirmed the reality of element 106. It was named ``seaborgium'' after the famed Berkeley chemist Glenn Seaborg.