The Environmental Defense Fund was started in the late 1960s by a small group of people who were concerned about issues like the toxicity of the pesticide DDT. He passed away at the age of 87.

Jonathan confirmed his father's death.

In the fall of 1965, he and about two dozen scientists, conservativists and high school students began gathering monthly in their homes on Long Island. They talked about environmental issues facing Long Island, including preserving wildlife habitats and dealing with pollution from the ground, and expressed their hopes for policy changes in letters to government officials and newspapers.

The group's unofficial leader was Mr. Cooley, who was a teacher at Bellport High School.

Charles Wurster, one of the founding fathers of the Environmental Defense Fund, recalled in an interview that Art was very good at dealing with people and making friends.

The group, which called itself the Brookhaven Town Natural Resources Committee, focused first on trying to stop the use of DDT, which Suffolk County had sprayed on marshes since the 1940s to control mosquitoes. It was a good target. Mr. Cooley and Dennis Puleston were aware of the effects of pesticides on the birds.

The committee's instrument of change was litigation. A state judge issued a temporary injunction against the use of DDT after it sued the Suffolk County Mosquito Control Commission.

The judge dismissed the lawsuit after the injunction stayed in effect for more than a year. The injunction gave the mosquito commission enough time to say it wouldn't use DDT for at least a year, and for the board of supervisors to outlaw its use. In 1971 it was banned by New York State.

The Environmental Defense Fund was incorporated in 1967, with the express purpose of going after DDT, according to Mr. Cooley.

The first meeting was in his living room. I chaired the meeting. I thought we should have a motion to proceed with due caution because of the fund's lack of financial resources.

Mr. Cooley, left, with two of the Environmental Defense Fund’s other founders, Charles Wurster, center, and Dennis Puleston, at the New York State Supreme Court in Riverhead, on Long Island, in 1987, two decades after their first lawsuit against the use of DDT was heard there.
ImageMr. Cooley, left, with two of the Environmental Defense Fund’s other founders, Charles Wurster, center, and Dennis Puleston, at the New York State Supreme Court in Riverhead, on Long Island, in 1987, two decades after their first lawsuit against the use of DDT was heard there.
Mr. Cooley, left, with two of the Environmental Defense Fund’s other founders, Charles Wurster, center, and Dennis Puleston, at the New York State Supreme Court in Riverhead, on Long Island, in 1987, two decades after their first lawsuit against the use of DDT was heard there.Credit...T. Charles Erickson

A lawsuit filed by the fund in Michigan halted the use of DDT and delayed the application of dieldrin in Western Michigan to fight Japanese beetles. The City of Milwaukee ended its use of DDT to fight Dutch elm disease because of a lawsuit. The Citizens Natural Resource Association filed a suit that led to the ban of DDT in Wisconsin.

In 1972 the Environmental Protection Administration banned the pesticide DDT with minor exceptions. The E.D.F. and other groups had filed a lawsuit against the federal government.

Mr. Cooley did not testify in the lawsuits because he was not an expert on the subject. He worked in the background with the Environmental Defense Fund while continuing to teach, and he advised the Students for Environmental Quality, a club that started in 1970 at his high school and gave its members a group outlet to pursue solutions to problems like pollution in Swan.

In the past, it was used as a vehicle for students to investigate other issues, learn about them and plot a course of action.

Arthur Paul Cooley was born on June 2, 1934, inSouthampton, on Long Island, and raised in Quogue. Harvey was a school principal and the mayor of Quogue. His mother was a homemaker who made furniture.

Mr. Cooley joined the staff of Bellport High School in 1956 after earning his bachelor's and master's degrees in biology from Cornell University. General science, ornithology, earth science, mathematics, and a course on gardening and wild foods were all taught by him.

Mr. Cooley served as the E.D.F.'s chairman from 1972 to 1975 and as an active board member until about a year ago. In the 2020 fiscal year, the fund reported $221 million in support and revenue.

Fred Krupp, the organization's president since 1984, said that he had enormous influence in the board. The generosity of spirit, not wanting to demonize anyone, became our path.

Mr. Cooley became a guide on exotic cruises around the world after he retired.

He is survived by his son and two grandsons. His marriage ended in divorce.

The impact of the battles against DDT was reflected in Mr. Cooley's book.

Four species returned to their original abundance bring joy and excitement to the skies of San Diego.