his seminal and far-reaching contributions in organic stereochemistry and for his wise and energetic leadership in professional societies that represent the interests of chemists and of society, both in the United States and abroad. P. Roy Vagelos (1995) For his fundamental contributions to the understanding of fatty acid biosynthesis, cholesterol metabolism, and phospholipid metabolism, and for his leadership at Merck that led to the discovery of a number of important therapeutic and preventive agents. Harold S. Johnston (1993) For his pioneering efforts to point out that man-made emissions could affect the chemistry of the stratosphere, in particular, the danger of the depletion by nitrogen oxide of the earth's critical and fragile ozone layer. Vladimir Haensel (1991) For his outstanding research in the catalytic reforming of hydrocarbons, that has greatly enhanced the economic value of our petroleum natural resources. See also List of chemistry awards References Awards established in 1991 Chemistry awards Awards of the United States National Academy of Sciences 1991 establishments in the United States