Maurice D. Hinchey, a former United States representative from New York who championed the environment and blue-collar workers in a political career of nearly four decades, died on Wednesday at his home in Saugerties, in the Hudson Valley. He was 79.

The cause was frontotemporal degeneration, a rare terminal neurological disorder, his family said.

Mr. Hinchey, a Democrat who retired from Congress in 2013 after 10 terms, began his political career as a state assemblyman in 1975. Within four years he became the chairman of the Assembly’s Environmental Conservation Committee. He served in the Assembly until 1992, when he was elected to Congress.

During his time on the state conservation committee, Mr. Hinchey led an investigation into Love Canal, an unfinished waterway in upstate New York that became one of the nation’s first major toxic dump sites. The revelations that emerged would force hundreds of families to evacuate and elevate concerns over toxic waste to national attention.