Chemical, Biological, Radiological, and Nuclear (CBRN)
Plain-language explanation
Chemical, biological, radiological, and nuclear hazards or threats. In AI safety, CBRN commonly appears when evaluating whether highly capable AI could meaningfully assist activities that create extreme physical harm.
Why It Matters
Frontier AI safety frameworks and catastrophic-risk laws may treat certain CBRN capabilities or assistance as severe-risk scenarios requiring heightened evaluation, safeguards, or reporting.
In Practice
CBRN stands for Chemical, Biological, Radiological, and Nuclear. U.S. government materials also use CBRNE when explosives are included.
In AI safety, the term does not mean that an AI system itself is a CBRN hazard. The concern is whether an AI capability could materially lower barriers to developing, obtaining, using, or causing harm involving CBRN agents or systems.
When a law or safety framework refers to CBRN-related risk, practitioners should use that source’s specific thresholds and definitions rather than assuming every discussion of hazardous scientific information constitutes catastrophic risk.