Which observation about federal assistance in nuclear preparedness is invalid?

The assertion that "very few buildings contain usable shelter space" is invalid because, historically, a significant number of structures across the United States have been evaluated and designated as fallout shelters. The identification of usable shelter space is part of federal initiatives aimed at enhancing public safety in the event of a nuclear incident. While some buildings may not have been updated or certified as effective shelters, there are indeed many that meet certain criteria for use during a nuclear emergency, contrary to the claim that very few exist.

The accuracy of the other statements helps to reinforce the framework of federal assistance in nuclear preparedness. The identification of fallout shelter space, the existence of radial monitoring with federal and state stations, and the establishment of the National Warning System with strategically located warning points all contribute to a robust emergency preparedness strategy designed to protect the public in case of a nuclear threat.