Daniel Alexander Okun, Kenan professor of environmental sciences and engineering at UNC-Chapel Hill, died Monday from complications with leukemia. He was 90.

According to his family, he was a jokester who would always stop at water treatment plants and dams during family vacations.

But he was also a patient and loyal father, and a loving, supportive grandfather.

"When my parents had their 50th anniversary, one of my children stood up and reflected that his happiest memories were growing up around his grandparents," Okun's son Michael said.

Okun was active on behalf of social justice causes for decades. He was at the front of picket lines, sit-ins and protests in Chapel Hill.

Daniel H. Pollitt, Kenan professor emeritus in the UNC-CH School of Law, came to the university in 1957 and remembers meeting Okun at an ad hoc committee meeting on integrating the Chapel Hill schools. Okun was the chairman of the committee.

They both fought for civil rights and protested the Vietnam War. Most recently, they've been decrying global warming and the war in Iraq.

"In all circles he was the leader, in social, in professional, in academic circles," Pollitt said. "He was a wonderful teacher and person. But he's been ailing in the last couple months. He's 90 years old. It's a blow, but not unexpected. But, God, I'll miss him."

Daniel Okun was born June 19, 1917, in New York City to Will Okun and Leah Seligman Okun, immigrants from Belarus in Eastern Europe.

He met his wife, Beth Griffin, in New Orleans when he was a young Army serviceman. They married and spent more than 60 years together.

He joined the UNC-CH faculty in 1952 and headed the sanitary engineering department from 1955 to 1973.

During that time, he transformed the program into the Environmental Science and Engineering program, now recognized as one of the best of its kind in the world.

He received the university's Thomas Jefferson Award. In 1999, the department honored him by establishing the Daniel A. Okun professorship with donations from former students, colleagues and friends.

He is survived by his wife, Beth; his brother, Milton Okun; his son, Michael Okun; his daughter, Tema Okun; and grandsons Will Okun and Joedan Okun.

A memorial service will be held at 2 p.m. Dec. 21 at the auditorium of the Carol Woods Retirement Community, 750 Weaver Dairy Road, Chapel Hill.

In lieu of flowers, the family requests that donations be made in Okun's memory to the Dan Okun Scholarship Fund at the School of Public Health, UNC-Chapel Hill, Campus Box 7407, Chapel Hill, NC 27599-7407.

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