| Ten miles: | 66 cal/cm2 |
| Twenty miles: | 14 cal/cm2 |
Thermal radiation at these levels was sufficient to produce first-degree burns on all exposed individuals within 28–30 miles and second-degree burns on exposed individuals within 22–24 miles. It is estimated that as much as 20 percent of the population received thermal burns beyond normal statistical projections due to the number of weapons and their detonation points, which had the effect of broadening the radiation-exposure range.
Limited ground observations by trained personnel have been possible only in some localities. The data, however, confirm the dispersive effects of thermal radiation from three weapons. Numerous incidences of flash burns and “ghost figures” of humans were noted.
7. RADIATION. Initial nuclear radiation was intense and, within a radius of 2 miles, virtually lethal to all life. Almost 100 percent of radiation produced occurred within 15 seconds. The following radiation doses have been calculated for the New York attacks:
| DISTANCE FROM BLAST CENTER | INITIAL RADIATION DOSE |
|---|---|
| Up to 2.4 miles | 100+ rems |
| Up to 2.1 miles | 500+ rems |
| Up to 2.0 miles | 1000+ rems |
It is estimated that the fatality rate at 500 rems is 70 percent; at 1000 rems it is almost universally 100 percent. Generally, the effects of initial radiation upon the individual depend upon his/her proximity to the blast center and degree of physical exposure. In terms of overall protection for individuals not exposed to the blast(s) directly, it can be noted that a minimum of 18 inches of concrete or similar material is necessary in order to reduce 1000 rems of radiation to a tolerable level of 100.
8. PHYSICAL EFFECTS. A thorough physical survey of the New York area has not been possible as of this date. Aerial photographs, however, reveal considerable damage to the Queens–Long Island areas, and severe-to- moderate damage to all adjacent areas. Given the variability of structures and terrain, the following damage table for the New York area has been constructed for each airburst:
| TYPE OF STRUCTURE | DAMAGE LEVEL | DAMAGE RANGE IN MILES FROM BLAST CENTER |
|---|---|---|
| 1. Wood houses and buildings | SEVERE | 12 Miles (average) |
| MODERATE | 14 Miles | |
| 2. Masonry buildings | SEVERE | 8.5 Miles |
| MODERATE | 10 Miles | |
| 3. Multistory wall-bearing buildings | SEVERE | 5.9 Miles |
| MODERATE | 7.3 Miles | |
| 4. Reinforced concrete buildings | SEVERE | 5.7 Miles |
| MODERATE | 7.0 Miles |
Relating this schema to blast pressure (as discussed in Section 5 of this Report), the following table can be generated:
| TYPE OF STRUCTURE | DAMAGE LEVEL | BLAST PRESSURE (PSI) |
|---|---|---|
| 1. Wooden buildings |
