A federal judge ruled this week that some nuclear weapons sites in the U.S. do violate environmental regulations.

On Thursday, a federal judge ruled that the National Nuclear Security Administration violated environmental regulations by failing to adequately assess the environmental impact of its plan to expand plutonium pit production at facilities in South Carolina and New Mexico.

The case involves a lawsuit that targeted a 2018 plan to establish two plutonium pit production sites—one at South Carolina's Savannah River and the other at Los Alamos National Laboratory in New Mexico. Plaintiffs argued the plan was based on an outdated environmental impact study, which failed to properly assess the implications of simultaneous production at both locations. They also insisted the plan weakened safety and accountability measures for the multibillion-dollar nuclear weapons program and its associated waste disposal.