The CEOs of the four largest US AI labs signed a public letter on June 3, 2026 urging Congress to require synthetic DNA and RNA providers to screen every customer and every order. OpenAI's Sam Altman, Anthropic's Dario Amodei, Google DeepMind's Demis Hassabis and Microsoft AI's Mustafa Suleyman are the headline signatories, alongside national security experts and executives from gene synthesis companies Twist Bioscience and Ansa Biotechnologies. The letter, organized by the nonpartisan Institute for Progress and the Foundation for American Innovation, argues that AI is rapidly lowering the knowledge barrier that has historically kept bioweapons out of reach.
The signatories warn that "there is a real possibility that the knowledge barriers which have historically prevented bad actors from obtaining biological weapons will meaningfully erode." The ask is regulatory: a federal mandate that any company selling printed DNA in the US has to vet who is buying it and what sequences they are ordering. A bipartisan bill introduced in the Senate earlier this year would do exactly that.
Custom gene synthesis is a mature commercial market. Arthur Kornberg first synthesized DNA in the 1950s; today dozens of companies operate commercial synthesizers that print sequences for research, drug development and diagnostics. Many providers only sell to vetted researchers and biotech firms, but vetting is voluntary and uneven, and AI now makes it easier to identify and exploit the gaps.
Key facts
- 01OpenAI's Sam Altman, Anthropic's Dario Amodei, Google DeepMind's Demis Hassabis and Microsoft AI's Mustafa Suleyman signed the June 3, 2026 letter.
- 02The letter, organized by the Institute for Progress and the Foundation for American Innovation, calls for mandatory screening of synthetic DNA and RNA orders.
- 03Canadian researchers reconstituted the extinct horsepox virus in 2017 using $100,000 worth of mail-order DNA, a case the signatories cite as precedent.
- 04A bipartisan Senate bill introduced earlier this year would require every US gene synthesis provider to screen orders and customers.
- 05Twist Bioscience and Ansa Biotechnologies, both members of the 2009-formed International Gene Synthesis Consortium, also signed.
The 2017 horsepox reconstitution is the canonical case the letter draws on. Canadian researchers assembled the extinct virus using $100,000 worth of mail-order DNA, and critics noted the same methodology would work on smallpox. Gene synthesis costs have continued to fall since, and large language models can now help design novel toxins and pathogens, though some hands-on biology training is still required to turn a digital sequence into a functioning virus.
The voluntary regime in place today runs through the International Gene Synthesis Consortium, which formed in 2009 and whose members screen orders against databases of "sequences of concern" tied to toxicity or pathogenicity. Twist Bioscience, an IGSC member, has publicly backed mandatory rules for years. "If you have technology that is capable of synthesizing DNA, then you should ensure that it's used responsibly, and part of that is making sure that you understand what you're making and who you're making it for," said James Diggans, the company's vice president of policy and biosecurity.
Federal guidelines from the Biden administration already require scientists and companies receiving federal funding to buy synthetic sequences only from providers that screen orders. The Senate bill would extend that obligation to every provider operating in the US, regardless of whether the buyer touches federal money. That closes the most obvious workaround: ordering through a non-screening vendor outside the federal funding net.
Screening alone is not enough, and the letter's signatories say so plainly. A Microsoft study published last year showed that AI protein design tools could generate sequences with structural similarity to known dangerous proteins, and those sequences slipped past existing screening software. The screen is matching against a library; the AI is generating around the library.
“It should be very difficult, if not impossible, to ask a model to help you do something imminently dangerous.”— Geoff Ralston, former president of Y Combinator and partner at Safe AI Fund
That gap is why the signatories want AI companies to do their own filtering at the model layer, refusing to help users design dangerous biology in the first place. The letter pushes the responsibility onto the labs that built the models — including the four whose CEOs signed it.
Stanford's David Relman, who signed the letter, frames it as a defense-in-depth argument rather than a single fix. "Given that the screening may fail in some cases, we must then have other points of control," he said. "That's where the AI companies are going to have to step up."
Bioterror attacks have historically been rare, but the failure mode the signatories are pointing at — an AI-assisted design that either intentionally or accidentally seeds a pandemic — is the kind of tail risk that policymakers have struggled to price. The letter is an attempt to force that pricing into legislation while the named labs still have leverage over how the rules are written.
For OpenAI, Anthropic, Google DeepMind and Microsoft, signing on is also a competitive move. A federal screening mandate paired with model-level refusals raises the compliance bar for any open-weights model or smaller lab that wants to ship biology-capable systems, and locks the incumbents' existing safety tooling in as the de facto standard. The companies pushing hardest for the rule are the ones best positioned to absorb its cost — a pattern that has played out in every previous wave of AI policy, from the Senate testimony circuit to the executive order on safety testing we covered last week.
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