Betty Jane Merrill, 48, who died Monday in a fire in her Silver Spring home, was active in singing groups in the Washington area.

A Montgomery County medical examiner said that Mrs. Merrill died of smoke inhalation as a result of a fire that broke out Monday in her home at 9313 Caroline Ave. Fire officials said the cause of the fire is under investigation.

Mrs. Merrill had sung with the University of Maryland chorus at the Kennedy Center for the Performing Arts in a production of Handel's Messiah in the early 1970s. She also belonged to the Montgomery Oratorio Society.

She had been a member of Christ Congregational Church in Silver Spring since 1969 and had traveled to both Canada and Europe as a member of the Church choir.

Mrs. Merrill had been active in the LaLeche League, an organization advocating "good mothering through breast feeding", since the 1960s. She also had been a league leader in the mother's organization.

A native of Washington, she was a 1949 graduate of Coolidge High School. She graduated from Purdue University in 1955 with a bachelor's degree in electrical engineering and worked for Douglas Aircraft in Long Beach, Calif., before returning to this area in 1958. She had resided in Silver Spring since that time.

Her marriage to John C. Merrill ended in divorce.

Mrs. Merrill is survived by two sons, Michael, of Silver Spring, and David, of Urbana, Ill., three daughters, Carol Merrill of Western Samoa, Cathy Merrill of Urbana; her mother, Pauline Bradburn of Silver Spring, and a sister, Margaret Sibson of Newport News, Va.