The military’s “heat ray” is meant to make people move by causing sharp pain at the skin’s surface. It can reach far beyond a handheld police tool. But “nonlethal” does not mean harmless, especially when someone cannot get away. Understanding DHS heat ray testing is crucial for evaluating its implications.

WASHINGTON, D.C. The Pentagon has agreed to let the Department of Homeland Security test an Active Denial System, or ADS, for possible use at the southern border, CNN reported October 21.

According to CNN, a September memo signed by Pete Hegseth allows a seven-month loan of one system. DHS would handle its use and develop procedures; Pentagon personnel would not operate it. The report does not identify a testing site or detailed safety plan.

The topic of DHS heat ray testing raises important questions about safety and ethics in law enforcement.

Permission to test is not proof of use against migrants. The loan details here rely on CNN’s reporting, not an independent review of the memo.

What does the heat ray do to a person?

ADS sends out invisible radio waves that quickly heat a thin layer near the skin’s surface. That real heating causes intense pain and an urge to move away. It is not just a trick played on the brain, and it does not shoot flames.

Sandia National Laboratories describes the energy reaching roughly 1/64 of an inch into skin, about 0.4 millimeters. This is a rough technical description, not a promise that deeper injury is impossible.

The intense heating sensation normally ends when the beam is switched off or a person leaves its path. A military scientist has also described tingling or tenderness that can linger for 10 to 15 minutes. That is not a recovery guarantee. A burn does not disappear just because the beam stops.

How far can it reach?

A 2015 article by military program officials describes an earlier ADS that made volunteers move away at distances up to 1,000 meters. That is about 3,280 feet, or six-tenths of a mile.

That result applies to the system tested, not every version. Smaller systems have been developed for shorter distances. The public reporting reviewed here does not establish the exact effective range of the unit loaned to DHS.

Long reach is part of the appeal: operators can apply force without moving close. It also raises a basic question: can they tell whether a distant person is refusing to move, or is unable to move?

Could a higher setting cause serious burns?

Too much heat can injure skin. Safety depends on limiting both the beam’s intensity and how long a person is exposed. Greater intensity or prolonged exposure can increase burn risk. The public record reviewed here does not establish what settings DHS operators would have or what limits would be enforced.

Burns have happened in testing. A 2009 National Defense University paper reported eight second-degree burns across more than 11,000 exposures involving about 700 volunteers. Six were small blisters; two required medical care. The paper reported recovery.

Those historical results show that injuries were uncommon in those tests, not impossible. They do not predict the risk to a baby, a trapped crowd or someone repeatedly exposed. “Nonlethal” describes the weapon’s intended purpose. It is not a guarantee about every outcome.

What protects children and babies?

The public evidence reviewed for this article does not establish safety for infants or children. The sources reviewed do not show a child-specific DHS safety plan. Volunteer test results are not proof that a baby cannot be badly burned.

A baby cannot move out of the beam alone. A young child may not understand what is happening. An adult with a disability, someone who has fallen, or a parent in a packed crowd may also be unable to escape. These are practical limits on a system that relies on people moving away, not measured injury rates for children.

Earlier designs had some safeguards. The 2009 paper describes a beam that stops when the operator releases the trigger or a preset time expires. Cameras help operators watch people and their reactions. These controls can limit exposure, but do not prove that children are protected.

DHS should answer these questions before any decision to use the system on people:

• Who must never be exposed? What rules protect children, babies, bystanders and people who cannot move?
• When must use stop? Who stops it if a person falls, cannot escape or appears injured?
• Is there a safe exit? Could people be pushed toward traffic, water, barriers or a crowd crush?
• What independent medical review is required? What care, injury reporting and follow-up would be available?

These are questions about needed protections, not claims that DHS has already adopted them.

A battlefield weapon or a police tool?

Compare ADS with a battlefield rifle: a rifle fires a bullet that can tear through tissue and kill. ADS was developed to drive people away through heat and pain, without a projectile. It is not a flamethrower, even though its nickname suggests one.

Its purpose overlaps with police tools that use pain or temporary loss of control. Pepper spray and tear gas cause chemical irritation. Batons and impact rounds strike the body. Tasers use electrical pulses. ADS uses heat delivered from a distance. Each has different risks; none is harmless.

The line blurs when military equipment built to control space is used to control civilians. Moving a person away may look like success to an operator, while that person may be fleeing into danger. The real test is not simply whether a tool is less deadly than a rifle. It is whether force is needed, whether it fits the threat and whether people can be protected.

United Nations guidance on less-lethal weapons calls for necessary and proportionate force, independent testing and special care for vulnerable people. It says directed-energy weapons liable to cause serious injury should not be used in policing. That guidance is not a court ruling on this reported DHS loan.

What should readers watch for next?

The key documents are the loan memo, a clear test plan, independent safety findings and rules for any proposed use. Testing a military device and approving it for civilian enforcement are different decisions.

The report does not announce a test in Utica or the Mohawk Valley. But the national question matters here too: who sets the limits when a tool designed for military missions becomes an option for civilian law enforcement?