"We are waiting for the results of the toxicologist's report from the medical examiner as to the cause of death," said a brother, Kevin R. Oster of Monkton.
The son of Edwin F. Oster Jr., an engineer, and LaRue K. Oster, a homemaker, Stuart Frederick Oster was born in Baltimore and raised in Lutherville.
A 1977 graduate of Calvert Hall College High School, Mr. Oster earned a bachelor's degree in biology and earth sciences from Frostburg State University in 1981.
Before joining the Howard County Health Department seven years ago, Mr. Oster had worked as an environmental health specialist for the Easton Health Department.
An automobile enthusiast, he particularly enjoyed driving his 1974 Jenson Healy roadster, family members said.
Mr. Oster also liked hiking, golfing, skiing and whitewater rafting on the Youghiogheny River in Western Maryland.
A memorial service will be held at 11 a.m. Saturday at Peaceful Alternatives Funeral and Cremation Center, 2325 York Road, Timonium.
In addition to his father, who lives in Lutherville, and brother, Mr. Oster is survived by another brother, Edwin F. Oster III of Lutherville.