Mario Molina, Nobel laureate who revealed threat to ozone layer, dies at 77

Mario Molina, who shared a Nobel Prize in chemistry for demonstrating the threat to the ozone layer posed by CFCs, chemical compounds often found in refrigerants and hair sprays and whose use was later curtailed by a landmark international accord, died Oct. 7 at his home in Mexico City. He was 77.

The cause was a heart attack, said Lorena Gonzalez, a spokeswoman at the Centro Mario Molina, a nonprofit environmental organization Molina founded in Mexico City.

Molina, a Mexican-born U.S. citizen, had a newly minted Ph. D. from the University of California at Berkeley when he joined the laboratory of F. Sherwood Rowland at the University of California at Irvine in 1973 as a postdoctoral fellow.

“The one project that intrigued me the most,” Molina wrote in a biographical sketch when he received the Nobel Prize, “consisted of finding out the environmental fate of certain very inert industrial chemicals — the chlorofluorocarbons ( CFCs) — which had been accumulating in the atmosphere and which at that time were thought to have no significant effects on the environment.”

CFCs were widely used in air conditioner and refrigerator coolants, spray paint, deodorant sprays and other aerosol products. Working with Rowland, Molina discovered that, far from having no significant effect on the environment, CFCs presented a grave risk to the ozone layer, a thin segment of the atmosphere that absorbs the ultraviolet rays of the sun. Unfiltered, those rays can cause skin cancer and other health problems in humans and damage the natural environment on Earth.

According to research by the two scientists, CFCs released into the atmosphere floated to ever higher altitudes, where they broke down and released chlorine atoms — even one of which could destroy 100,000 ozone molecules.

“We were alarmed at the possibility that the continued release of CFCs into the atmosphere would cause a significant depletion of the Earth's stratospheric ozone layer,” Molina wrote.

In 1974, he and Rowland published their findings in the journal Nature. They met fierce resistance from industry leaders whose lucrative businesses relied on CFCs. In 1977, according to the Los Angeles Times, the chief of one aerosol manufacturer alleged that their theory was “orchestrated by the Ministry of Disinformation of the KGB.”

But in 1985, British researchers tracking ozone readings in the Antarctic announced the discovery of a significant thinning — a hole, as it became known — in the ozone layer above the South Pole.