Pentagon Approves Testing of ‘Heat Ray’ Weapon for Potential Use at US-Mexico Border

The Pentagon has authorized the US Department of Homeland Security (DHS) to test a military-developed weapon known as a “heat ray” for potential use along the US-Mexico border, raising questions about the role of directed-energy technology in immigration enforcement.

US Defense Secretary Pete Hegseth approved a seven-month loan of the Active Denial System (ADS), according to a memorandum reported by CNN on October 21, 2026. The arrangement would allow DHS to evaluate the technology and develop potential tactics for its use.

The authorization does not mean the weapon has been deployed at the border. Its eventual use in immigration enforcement would depend on further evaluation and operational decisions.

How the Heat Ray Weapon Works

The Active Denial System uses high-frequency electromagnetic waves to heat the surface of human skin, producing an intense burning sensation intended to make people move away from the beam.

Unlike conventional firearms, the system is designed to deter or disperse people without firing a projectile. Its effects are intended to stop when a person moves out of the beam’s path.

The US military developed the technology for crowd-control purposes. Although it is described as a non-lethal system, exposure can cause injury under certain circumstances, making safety procedures and limits on its use important considerations.

The system’s ability to affect people from a distance is one reason it has attracted interest for security operations. However, its effectiveness and suitability for conditions along the southern border would need to be assessed.

Why the Pentagon Is Considering the Technology

The latest authorization revives an idea previously considered by US border officials.

In 2018, Customs and Border Protection examined the possibility of using the technology against groups of migrants. The proposal was not adopted at the time, according to CNN’s reporting.

The renewed evaluation comes as the Trump administration continues to prioritise immigration enforcement and border security.

A seven-month loan would give DHS time to assess the system’s capabilities and develop procedures for possible use. The authorization itself, however, does not establish a deployment date or confirm that officers will use the weapon against migrants.

Safety and Legal Concerns

The prospect of introducing a military-developed energy weapon into border enforcement raises questions about the use of force, potential injuries and the risks facing people in the surrounding environment.

The consequences could be particularly serious in areas near rivers, steep terrain or crowded border crossings, where a person reacting to intense heat might move into a hazardous situation.

There are also questions about how authorities would prevent unintended exposure and determine when using the technology would be proportionate and lawful.

Any decision to deploy the system would need to account for these risks, alongside the practical challenges of operating it in changing weather and terrain.

The weapon’s designation as non-lethal does not eliminate the possibility of injury or remove the need for clear operating rules and accountability.

Testing Does Not Mean Deployment

The Pentagon’s authorization allows DHS to evaluate the Active Denial System, but several questions remain unanswered, including where testing will occur, what operational scenarios will be examined and whether the department will eventually seek to use the technology at the border.

The distinction matters because approval to test a weapon is not the same as authorization for routine use against migrants.

For now, the decision places the heat ray back under consideration as a potential border-security tool. Whether it advances beyond testing will depend on the results of the evaluation, operational requirements and decisions by federal authorities.

The proposal nevertheless highlights the growing debate over how far the US government should go in adapting military technologies for domestic immigration enforcement.