American environmentalists

Clair Cameron Patterson (June 2, 1922 – December 5, 1995) was an American geochemist. Born in Mitchellville, Iowa, Patterson graduated from Grinnell College. He later received his Ph.D. from the University of Chicago and spent his entire professional career at the California Institute of Technology (Caltech).
In collaboration with George Tilton, Patterson developed the uranium–lead dating method into lead–lead dating. By using lead isotopic data from the Canyon Diablo meteorite, he calculated an age for the Earth of 4.55 billion years, which was a figure far more accurate than those that existed at the time, and one that has remained largely unchallenged since 1956.
Patterson first encountered lead contamination in the late 1940s as a graduate student at the University of Chicago. His work on this subject led to a total re-evaluation of the growth in industrial lead concentrations in the atmosphere and the human body, and his subsequent activism was seminal in the banning of tetraethyllead in gasoline and lead solder in food cans.

David W. Orr is the Paul Sears Distinguished Professor of Environmental Studies and Politics Emeritus at Oberlin College, and presently Professor of Practice at Arizona State University.
During his tenure at the Environmental Studies Center at Oberlin College, Orr demonstrated how institutions of higher learning can teach ecological literacy while practicing sustainable design and encouraging more eco-friendly lifestyles on campus. Orr's books, Ecological Literacy: Education and the Transition to a Postmodern World (1992) and Earth in Mind (1994-2004), proposed ways in which education should evolve to emphasize sustainability, not only in the narrow parameters of ecology-based programs, but in wider curricula, from political science and economics to liberal arts.

James Vincent McNichol III (born July 2, 1961), known professionally as Jimmy McNichol, is an American actor and singer who first gained fame as a teen idol in the late 1970s. At the beginning of his career his popularity quickly grew, causing networks like CBS to create and implement multiple television series specifically for his involvement and leading roles. After making a record number of appearances on top talk shows he was viewed by many as "the face you see everywhere."In 1978, McNichol recorded an album with his sister, Kristy, also a child actress, and the two went on to host a youth-oriented variety show for ABC. McNichol subsequently had lead roles in Smokey Bites the Dust (1981), and opposite Susan Tyrrell in the horror film Butcher, Baker, Nightmare Maker (1981). After retiring from acting in the 1990s, McNichol relocated with his family to Colorado, and has been active in environmentalist causes, and working as a real estate investor and home renovator.

Carmen Sylvia Mathews (May 8, 1911 – August 31, 1995) was an American actress and environmentalist.

Ann Cottrell Free (June 4, 1916 – October 30, 2004) was an American journalist who wrote extensively on animal protection issues.

Robert Landis Armstrong, known as Bob Armstrong (November 7, 1932 – March 1, 2015), was a Democratic politician and an environmental activist from the U.S. state of Texas. He was a member of the Texas House of Representatives from 1963 to 1971, Commissioner of the Texas General Land Office from 1971 to 1983, and a member of the Texas Parks and Wildlife Commission from 1985 to 1991. From 1993 to 1998, he was the assistant secretary for land and minerals management at the United States Department of the Interior under appointment of U.S. President Bill Clinton.