The National Security Agency has released new guidance urging operators of critical infrastructure to adopt zero-trust security principles in operational technology systems. In its October 8 announcement, the agency identifies risks affecting industrial systems that support energy, water, agriculture, public health and government operations. Unlike conventional corporate networks, operational technology frequently controls physical equipment and processes, making service disruption a potential public-safety issue. The guidance recommends continuous verification of users, devices and communications rather than assuming that activity inside a network is trustworthy. Although primarily directed toward national-security and defense-related systems, the recommendations have broader relevance for infrastructure operators. The release reflects growing concern that cybersecurity failures can extend beyond stolen information to interruptions in services communities depend upon.