The city's long-time chief medical examiner is stepping down.

Dr. Charles Hirsch is retiring from the post he was appointed to in 1989 by the late Mayor Ed Koch.

The 75-year-old investigated thousands of deaths in the city, ranging from the 87 people who died in the Happy Land Social Club fire in 1990, to the nearly 3,000 killed in the September 11th attacks.

He also oversaw major advancements in DNA identification and response operations to mass fatalities.

In a statement, Mayor Michael Bloomberg called Hirsch "a visionary," and says he was often referred to as "the father of modern forensic pathology."

Hirsch's deputy, Dr. Barbara Sampson, is now serving as the city's acting Chief Medical Examiner.