By Gabriel J.X. Dance

Kevin Esvelt, a genetic engineer at the Massachusetts Institute of Technology, shared conversations in which OpenAI’s ChatGPT explained how to use a weather balloon to spread biological payloads over a U.S. city. In another chat, Google’s Gemini ranked pathogens by how much they could damage the cattle or pork industries. Anthropic’s Claude produced a recipe for a novel toxin adapted from a cancer drug. Other chats contained information that Dr. Esvelt — known in his field as something of a Cassandra — felt was too dangerous to share.

Dr. Esvelt has for years warned scientists, journalists and lawmakers about the dangers of synthetic biology if left unchecked. In 2023, he helped craft a stunning demonstration of how chatbots had raised the stakes.

He asked ChatGPT to help him assemble a pathogen that could cause mass death. The bot provided accurate instructions, even outlining which raw materials to buy. He put the unassembled biological pieces into test tubes and packed them in a box, which a colleague then brought to a White House meeting on biological risks.

Dr. Esvelt has continued to probe leading chatbots, sometimes posing as a crime writer seeking plausible methods of spreading viruses, or as an ethicist trying to educate others. Often he plays a version of himself: a scientist exploring the intricacies of virology.

“Anything where there isn’t an expert warning them, they can’t fix,” said Dr. Esvelt, who has consulted for Anthropic and OpenAI. He said the industry should censor a wider swath of biological information and share it only with approved users.