Missouri removes old pollution rules after they expired

US environmental regulators are approving Missouri's request to remove two old rules about nitrogen oxide emissions. These rules, which applied to power plants and other industrial facilities, had already expired.

This document is a cleanup operation. The rules it removes were already sunsetted, meaning they had a built-in expiration date and are no longer in effect. This is not a change in environmental policy, but rather a bureaucratic update to reflect a change that already happened.