President Donald Trump’s homeland defense agency has taken the first steps to defend the nation against an electromagnetic pulse attack which could instantly destroy tens of millions of vital electronic devices from coast to coast.

Pentagon officials have quietly worried for decades about an enemy using a high-altitude nuclear explosion to create a nationwide EMP attack. But little or nothing has been done because of the huge cost of protecting civilian electronics and the nation’s electrical, transport and energy infrastructures.

The plan from the Department of Homeland Security showcases the EMP problem, and offers initial planning steps — but it does not urge major spending or an award of tax-breaks to help companies, utilities, and local governments protect their networks from EMP.

“An intentional electromagnetic pulse (EMP) attack or a naturally occurring geomagnetic disturbance … could damage significant portions of the Nation’s critical infrastructure, including the electrical grid, communications equipment, water and wastewater systems, and transportation modes,” says the DHS plan, titled “Strategy for Protecting and Preparing the Homeland Against Threats of Electromagnetic Pulse and Geomagnetic Disturbances.”

“We need to do a whole lot more on that,” Wisconsin Sen. Ron Johnson told DHS Secretary Kirstjen Nielsen at an Oct. 10 hearing.

But Nielsen has little authority to write regulations which would require anti-EMP protections be added over vulnerable networks and little money to fund any protections. So the DHS plan sketches out three goals:

Improve risk awareness of electromagnetic threats and hazards … Enhance capabilities to protect critical infrastructure from the impact of an electromagnetic incident … Promote effective electromagnetic-incident response and recovery efforts.

But other agencies have the authority to demand EMP protections be added to seaports and hospitals, telephone networks, traffic lights, railroad junctions, electrical generators and transformers, gasoline pipelines, Wall Street and Silicon Valley, for example.

The DHS plan suggested officials may soon be directed to write those regulations by a Presidential order:

A draft executive order on coordinating national resilience to electromagnetic pulse incidents is currently being developed under the auspices of the National Security Council staff in coordination with Federal departments and agencies. Upon issuance, the executive order will obviously inform—and potentially alter—the Department’s approach to the EMP-GMD threat that is articulated in this DHS Strategy.

The EMP threat was recognized in 1962 when a high-altitude nuclear test — dubbed “Starfish Prime” — knocked out streetlights and telephone service in Hawaii, 900 miles distant.

The DHS document said:

Extreme electromagnetic incidents caused by an intentional electromagnetic pulse (EMP) attack or a naturally occurring geomagnetic disturbance (GMD, also referred to as “space weather”) could damage significant portions of the Nation’s critical infrastructure, including the electrical grid, communications equipment, water and wastewater systems, and transportation modes. The impacts are likely to cascade, initially compromising one or more critical infrastructure sectors, spilling over into additional sectors, and expanding beyond the initial geographic regions. EMPs are associated with intentional attacks using high-altitude nuclear detonations, specialized conventional munitions, or non-nuclear directed energy devices. Effects vary in scale from highly local to regional to continental, depending upon the specific characteristics of the weapon and the attack profile. High-altitude electromagnetic pulse attacks (HEMP) using nuclear weapons are of most concern because they may permanently damage or disable large sections of the national electric grid and other critical infrastructure control systems.

The DHS report did not say when White House would issue an executive order.