Paul T. “Tito” Cosimano, former plant operations engineer of the Arlington County Water Pollution Control Plant, died Nov. 28 at his home in Kensington, Md.. He was 85.

The cause was atherosclerotic cerebrovascular disease, said his daughter, Anne Cosimano.

Mr. Cosimano began working at the water pollution control plant as a chief chemist in 1957 and retired as the head of the Arlington County facility in 1994.

In addition, he worked a lab technician at Prince George’s Hospital Center from 1953 until 1970.

Paul Titus Cosimano, a native Washingtonian, was a 1945 graduate of Gonzaga College High School and a 1949 analytical chemistry graduate of Georgetown University. He was a Korean War veteran.

Mr. Cosimano was past secretary and treasurer of the Arlington County Retirement Board and past president and former board member of the Arlington Community Federal Credit Union. He served on science advisory board of Northern Virginia Community College and was a member of American Chemical Society.

He coached women’s slow-pitch softball in Montgomery County and was inducted into Washington Metropolitan Softball Hall of Fame in 1985. He moved to Kensington from Washington in 2011.

Survivors include his wife of 62 years, Patricia Pyatt Cosimano of Kensington; seven children, Jeanne Cosimano of Washington, Mary Cosimano of Baltimore, Anne Cosimano of Silver Spring, Stephen Cosimano of Wheaton, Md., Kathleen Stephanides of Nicosia, Cyprus, Paul Cosimano of Sarasota, Fla., and Carl Cosimano of Port St. Lucie, Fla.; and eight grandchildren.

— Megan McDonough