In the first post of this series, I described what happens to the human body at ground zero of a 10 to 15-kiloton nuclear detonation: the zone within 800 meters of the hypocenter. There, the thermal pulse delivers over 100 calories per square centimeter to the skin, carbonizing the epidermis and dermis before a single nerve ending can fire a pain signal.

The blast wave, arriving a fraction of a second later with overpressures exceeding 10 psi and winds above 500 kilometers per hour, collapses every structure and turns the debris into projectiles. The initial radiation, exceeding 50 Gray at close range, shatters the DNA of every cell in the body. Three lethal mechanisms delivered almost simultaneously. No one survives unshielded. No burn unit, no trauma surgeon, no field hospital can change the outcome. At ground zero, medicine has nothing to offer except documentation.

This is Part II. One mile. The Moderate Damage (MD) zone, extending from 0.8 to 1.6 kilometers from the hypocenter of a 10 to 15-kiloton detonation. This is where medicine becomes cruel. Not because it is absent, but because the victims survive long enough to need it, and there is no one left to provide it.

The survivors who should not have survived

At one mile from the hypocenter, the thermal fluence drops to approximately 8 to 20 calories per square centimeter. This is no longer enough to carbonize tissue on contact. It is enough to produce second and third-degree burns on all exposed skin within a fraction of a second. The epidermis blisters, separates from the dermis, and in areas of direct exposure the full thickness of the skin is destroyed.

Clothing offers variable protection: dark fabrics absorb more thermal energy and can ignite, while lighter materials may reflect enough to reduce burn depth. In Hiroshima, survivors at this distance bore the thermal imprint of their clothing patterns on their skin, the dark portions of kimono designs seared into the flesh while the light portions left the underlying skin relatively intact.

The eyes, if directed toward the fireball, suffer flash blindness or permanent retinal burns depending on the duration of gaze. Unlike at ground zero, where the entire globe is destroyed, at one mile the retinal burn is focal. A person who happened to glance at the fireball would lose central vision permanently while retaining peripheral sight. A person who was looking away might retain full vision. The difference between blindness and sight at this distance is determined by the direction of a single glance in a fraction of a second.

The blast wave at the inner boundary of the MD zone arrives with an overpressure of approximately 3 to 5 psi and winds of 100 to 200 kilometers per hour. This is not enough to flatten reinforced concrete structures, but it is enough to shatter every window in every building within the zone. And in a modern city, windows are everywhere.

A standard glass pane shatters at approximately 0.5 to 1 psi. At 3 psi, the glass fragments into hundreds of projectiles traveling at velocities sufficient to penetrate human skin, muscle, and in some cases the thoracic or abdominal cavity. Studies of blast injuries from conventional explosions have documented glass fragments embedded in vital organs at distances where the overpressure itself was survivable. At one mile from a nuclear detonation, the glass becomes the weapon. The overpressure is the delivery mechanism.

The FEMA planning guidance for nuclear detonation response identifies the MD zone as the area where the greatest number of salvageable casualties will be found. The majority of those casualties will present with penetrating glass injuries combined with thermal burns. The combination is what kills.

The lethal arithmetic of combined injury

This is where the medicine of nuclear weapons diverges from everything taught in civilian trauma courses. A patient with 30% total body surface area burns, if treated in a modern burn center with fluid resuscitation, wound care, and infection control, has a survival rate exceeding 90%. A patient exposed to 2 Gray of whole-body ionizing radiation, if treated with supportive care and growth factors, has a survival rate exceeding........

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