This legislation, titled the Cell-Site Simulator Warrant Act of 2025, aims to significantly regulate the use of cell-site simulators by law enforcement and intelligence agencies. It establishes a general prohibition on the knowing use of these devices in the United States by any individual or entity, and by the intelligence community outside the U.S. if the target is a U.S. person. Violations of this prohibition carry a substantial fine of up to $250,000. Information or evidence acquired through unlawful cell-site simulator use is generally inadmissible in court, with an exception for proceedings related to the violation itself. The bill outlines several exceptions to the general prohibition, primarily requiring a warrant for law enforcement use. To obtain a warrant, agencies must demonstrate that other investigative procedures have failed or are too dangerous, specify the simulator's area of effect and operating time, and certify that the scope is the narrowest possible. Warrant applications must also disclose potential disruptions to commercial mobile services, including emergency calls (like 9-1-1 and suicide hotlines), and certify that the specific simulator model has been inspected by an FCC-recognized third-party lab. Courts are required to weigh the government's need against potential negative side effects and cannot grant warrants that risk public safety or unreasonably inconvenience the community. Warrants are limited to 30 days, with extensions possible under similar strict conditions. An emergency exception allows for immediate use in cases of immediate danger, organized crime, or national security threats, provided a warrant application is submitted within 48 hours. However, if the emergency warrant is denied, all collected information must be promptly destroyed. The bill also mandates notice to individuals whose devices were affected, typically within 90 days, though this can be postponed for good cause. Further exceptions include foreign intelligence surveillance conducted under FISA, good-faith research or teaching by non-governmental entities, and protective services by the Secret Service (though data from such use is inadmissible in criminal proceedings). Correctional facilities may use contraband interdiction systems under specific conditions, including limiting transmissions to facility property, posting signs, and complying with FCC regulations. Law enforcement testing and training are also permitted under strict guidelines to ensure data minimization and destruction. The bill defines a cell-site simulator as any device simulating a base station to identify, locate, or intercept transmissions for purposes other than ordinary commercial mobile services. It clarifies that collected information should primarily identify nearby devices and signal strength, requiring compliance with wiretapping or tracking device laws for content interception or tracking. The Attorney General must adopt and publish minimization procedures for incidentally collected data, ensuring its destruction. Individuals subjected to unlawful cell-site simulator operations can bring civil actions for relief, including damages and attorney fees. The bill also establishes administrative discipline procedures for willful violations by government officers or employees. Annual joint reports from various Inspectors General are mandated to assess compliance, track warrant applications, emergency uses, and the number of targeted and incidentally affected devices. Finally, the Federal Communications Commission is directed to initiate proceedings to promulgate or modify regulations to implement the Act within 180 days of enactment. Most provisions of the bill will take effect two years after enactment, with a possible one-year extension for existing cell-site simulator models if the Attorney General certifies additional time is needed for independent testing.