Art Cooley, 87, a longtime activist who cofounded the Environmental Defense Fund more than 50 years ago, died Jan. 30 in Colorado of natural causes, said his son, Jonathan. Cooley helped launch the group, now one of the world’s leading environmental organizations, from his living room on Long Island, New York, in 1967. In the mid-1960s, while a high school teacher, Cooley was one of several activists who organized to stop use of the pesticide DDT. The legal battle led to the banning of DDT in the United States and the formation of EDF. Cooley was involved with the organization’s board, including as its chair and later secretary, for decades.