Which statement is true about the disposal of materials with a half-life of 120 days or less?

The statement regarding the disposal of materials with a half-life of 120 days or less being disposed of in regular trash when levels reach background is accurate due to the principle of radioactive decay and the established safety standards for managing radioactive waste.

Materials with a half-life of 120 days will decrease in radioactivity significantly over time. According to regulatory guidelines, if these materials are allowed to decay to a point where their radioactivity levels are indistinguishable from background radiation, they are considered safe and may be disposed of in regular waste. This process ensures that any potential hazard is minimized and aligns with responsible waste management practices.

In scenarios with longer half-lives or when waste cannot reach background levels, alternate disposal methods may be required, such as incineration or special hazardous waste disposal, which is necessary for materials that retain their radioactive properties for extended periods and pose ongoing risks. Storing materials indefinitely is also not a sustainable practice, as it does not address the radioactive risk and can lead to compliance issues with regulations concerning waste management.