The Pentagon has given the Department of Homeland Security permission to test a military-grade heat ray and develop tactics to potentially use it in operations at the southern U.S. border, according to a memo signed by Defense Secretary Pete Hegseth last month and obtained by CNN.
The weapon, officially known as the Active Denial System, fires an invisible beam of electromagnetic waves that can reach more than half a mile. When the beam touches human skin it causes an intense burning sensation — which Pentagon officials have previously compared to feeling a blast of heat when opening a hot oven — along with what the military calls “an instinctive and irresistible urge to run from the effect.”
The memo authorizes the “temporary loan” of one ADS system to DHS for seven months, starting in September, and states that it “shall not be operated by DoW personnel” — appearing to absolve the Pentagon of responsibility for how the system may ultimately be deployed, according to CNN’s reporting.
An unprecedented step
Deploying the heat ray at the U.S. border would be an unprecedented step, even for an administration that has made border security and immigration enforcement a top priority. The DHS request did not specify where or how the weapon would be tested or how it might eventually be used, but over the years there have been internal discussions about using it for crowd dispersal along the U.S.-Mexico border, according to current and former Customs and Border Protection officials.
U.S. officials also considered deploying the system during moments of domestic unrest, including at the end of Trump’s first term when protests erupted over the murder of George Floyd, according to a former U.S. official familiar with those discussions.
Questions about safety and precedent
The military has long described the Active Denial System as nonlethal, saying the tingling effect lasts 10 to 15 minutes. But critics question the safety of firing directed-energy weapons at civilians, the practical effectiveness of the system, and the legal safeguards required when a domestic agency uses pain-inducing technology for immigration enforcement.
Civil liberties advocates are expected to challenge any operational deployment in court. For now, the authorization covers testing and tactics development only — not use against migrants.
