Northampton - Barbara Hatch Rosenberg Cavalieri passed away peacefully at home at the age of 97 on Saturday, March 14, 2026 in Northampton, Massachusetts.

Barbara Cavalieri, known professionally as Dr. Barbara Hatch Rosenberg, was an expert in biological and chemical weapons with a PhD from Cornell University. Born on June 28, 1928, in New York City, she was the daughter of Arthur Hatch and Evelyne Schreiber Hatch and sister to Richard Hatch and Joan Joshi. She and Liebe F. Cavalieri shared 43 years of marriage filled with love and companionship until his passing in 2013.

She was the founder of the Scientists Working Group on Biological and Chemical Weapons, established in 1989. As the Cold War came to an end, the Working Group was the first voice calling for strengthening the Biological Weapons Convention and the norm against biological weapons. Her work in biological warfare led to her becoming an Advisor to the U.S. Congress Office of Technology Assessment study of Weapons of Mass Destruction in 1993-4 and then as a member of a prestigious panel of scientists that advised President Clinton, the Secretary of Defense and the Secretary of Health on biological weapons issues in 1998. She was a member of the United States National Academy of Sciences, Engineering and Medicine (NASEM) Working Group on Biological Weapons. She was also an officer of ProMED-mail, the first global electronic rapid reporting system for outbreaks of emerging diseases, which was launched by the NASEM Working Group in 1994 as a prototype and later became its own independent entity.

Trained as a molecular biologist, Dr. Rosenberg was for many years a cancer researcher at Memorial-Sloan-Kettering Cancer Center in New York and was Associate Professor of Biochemistry at Cornell Medical College. On leaving those positions she became a Research Professor at the State University of New York at Purchase, where she devoted most of her activity to biological weapons issues. She prominently questioned official accounts of the 2001 US Mail anthrax attacks that followed 9/11, and was profiled in The New Yorker, Vanity Fair and The Atlantic among other media outlets.

Among numerous honors, she was elected a fellow of the American Cancer Society, a fellow of the Institut National de la Santé et de la Recherche Médicale, a Member American Society Biochemistry and Molecular Biology and Sigma Xi.

Barbara, known affectionately as ‘Mouse’ to her step-grandchildren and step-great-grandchildren, had impeccable style and loved classical music, French wine and cheese, her beloved pet cats, traveling, and fresh cut flowers. She was an avid gardener and eagerly read the New York Times every day. She is survived by her step-daughters Claudia Kellogg and Frances Cavalieri, of Connecticut, along with 11 step-grandchildren and 12 step-great-grandchildren.

Contributions in her honour to the Union of Concerned Scientists (https://www.ucs.org/) would be appreciated.