Shirley A. Briggs, 86, an illustrator, writer and former executive director of the Rachel Carson Council, a group that educates the public about toxic chemicals, died Nov. 11 at the Sycamore Acres nursing home in Derwood. She had cardiopulmonary failure.

Ms. Briggs knew Carson when both worked in the mid-1940s at the U.S. Fish and Wildlife Service. She later helped Carson do research for "Silent Spring" (1962), a book credited with alerting the American public to the dangers of environmental pollution.

After Carson's death from cancer in 1964, Ms. Briggs helped establish what is now the Rachel Carson Council to help scientists and lay people answer questions about pesticides and other chemicals. She was executive director from 1970 to 1992. "What we are is a resource organization, not an activist group," she once told an interviewer.

Her other longtime affiliation was with the Audubon Naturalist Society, which she and Carson joined to take advantage of its organized trips to naturalist sites. Ms. Briggs soon was editing and illustrating its publications, teaching conservation principles to members and conducting bird counts in her efforts to showcase how the parklands of Washington could be harmed by the construction of dams and highways.

In January 1962, during a bird count for starlings, she told a Washington Post reporter, "You don't know how many of those little rascals there are until you stand and count them on a cold night."

Shirley Ann Briggs, the daughter of a university political science professor, was a native of Iowa City, and she spent her childhood summers in wilderness camps nationwide. She was a graduate of the University of Iowa, where she also received a master's degree in sculpture.

At the university, she was a student of Grant Wood, the artist best known for "American Gothic." According to a published report, her father had been the model for Wood's "Parson Weems' Fable." She was a lifelong admirer of Wood's work.

In the early 1940s, Ms. Briggs moved to Baltimore to illustrate airplane manuals for the Glenn L. Martin Aircraft Co. She later described her job as drawing pictures so that "the mechanics would know how to grease a B-26."

In Washington, she later did graphics and writing work for the Fish and Wildlife Service; became chief of the Bureau of Reclamation's graphics section; and drew dioramas depicting natural habitats for the Smithsonian Institution's National Museum of Natural History.

In 1992, she and the staff of the Rachel Carson Council published the book, "Basic Guide to Pesticides: Their Characteristics and Hazards." For that effort, Ms. Briggs received the Environmental Protection Agency's Rachel Carson Award. The council was based in Chevy Chase during her tenure and is now in Silver Spring.

She leaves no immediate survivors.

Ms. Briggs, shown in 1951, led the Rachel Carson Council for 22 years.