Warday

DECLASSIFIED 5/16/93

SUMMARY REPORT ON EARLY DOMESTIC FALLOUT

JANUARY 5, 1989

EMERGENCY TASK FORCE ON DOMESTIC FALLOUT

U.S. DEPARTMENT OF ENERGY

INTRODUCTION

The Emergency Task Force on Domestic Fallout was created on December 15, 1988, as an interdepartmental unit to gather, assess, and monitor the radioactive fallout produced by the October 28, 1988, Soviet surprise attack against the United States. Data are presently being collected by field-based units within the Department, as well as from military and local government sources. This report is concerned only with the early fallout produced by the October attack, that is, the fallout produced and deposited within the first few days after the attack.

As a result of the Soviet attack, many monitoring facilities in the attack zones were either destroyed or disabled. Manned ground monitoring stations have been established on an emergency basis near bombed zones where human safety could be assured. Extensive remote/robot stations have been placed by helicopter or air-dropped into highly radioactive areas.

The purpose of this network has been to chart the extent and course of atmospheric fallout. A list of active major data collection stations appears in Attachment One.

For background purposes, each attack zone is briefly described in terms of target nature, weapon yield, etc. An abbreviated description of the causes and nature of radioactive fallout appears in Attachment Two.

This is a summary report only. Full details, as they are presently available, appear in other DOE documentation.

PARAMETERS

Radioactive fallout is an aftereffect of a nuclear detonation. Its nature, intensity, and range are results of weapon type (fission, fusion, or mixture), burst height (ground- or airburst), yield of weapon (usually calculated in megatons), and wind and other meteorological conditions. Brief coverage of these variables is presented in this report.

GENERALIZED OBSERVATIONS

For comparison purposes, the October 1988 Soviet strike may be considered two attacks: one against U.S. urban centers and another against underground missile installations. As a consequence, the Soviets employed different attack strategies, which in turn produced different fallout patterns.

The attacks against urban centers utilized air and ground detonations, which resulted in both local fallout and broad distribution through the upper atmosphere. The attacks against missile silos produced intense ground-level radiation and severe long-range fallout. In both attacks, however, the multiplicity of warheads combined to produce aggravated fallout conditions.

The nature and extent of the attack and the prevailing winds produced in each case a unique fallout distribution. Some generalized, or averaged, comparisons can be drawn, however. In the case of the attacks on urban centers, it can be estimated that the following unit-time fallout conditions occurred similarly for all three attacks:

DOWNWIND DISTANCE FROM GROUND ZERO	DOSE RATE IN ROENTGENS/HOUR
50 MILES	1600 R/HR
100 MILES	360 R/HR
200 MILES	125 R/HR
300 MILES	55 R/HR
400 MILES	20 R/HR
500 MILES	6 R/HR

At the end of the first week, it is estimated that the dose rate for these distances was as follows:

50 MILES	3400 R/HR
100 MILES	2700 R/HR
200 MILES	405 R/HR
300 MILES	144 R/HR
400 MILES	42 R/HR
500 MILES	12 R/HR

In the case of the ground attack on missile silos, the following conditions are estimated:

DOWNWIND DISTANCE FROM GROUND ZERO	DOSE RATE IN ROENTGENS/HOUR
50 MILES	1400 R/HR
100 MILES	320 R/HR
200 MILES	75 R/HR
300 MILES	30 R/HR
400 MILES	8 R/HR
500 MILES	1.2 R/HR

Dosage rates for the end of the first week are estimated to have been as follows:

50 MILES	2200 R/HR
100 MILES	270 R/HR
200 MILES	68 R/HR
300 MILES	16 R/HR
400 MILES	3.2 R/HR
500 MILES	.8 R/HR

These are averaged estimates only, which have been scaled according to previously known fallout characteristics and limited current data. Complete analysis will not be available for some time, although local government and military authorities have been advised about fallout hazards and subsequent medical/health consequences.

REVIEW OF RADIOACTIVE FALLOUT CONDITIONS

A brief summary of fallout conditions and patterns is presented in the following target-by-target descriptions:

1. NEW YORK CITY—LONG ISLAND AREA

NATURE OF TARGET: Urban center.

TYPE/YIELD OF SOVIET WEAPON: Missile-delivered thermonuclear warhead in 9–10-megaton (MT) range.

NUMBER OF WARHEADS DELIVERED: Three land targets, with some evidence of several other weapons that detonated at sea.

BURST TYPE: Airburst and groundburst.

SPECIAL FEATURES: High concentration of fission elements suggests “dirty weapon” type designed to increase fallout intensity of groundburst.

FALLOUT PATTERN: There was a frontal system active in the New York City area on this date, developing winds from a WNW direction at 10–12 knots. As a consequence, little upwind fallout occurred in upper New York—Connecticut area; most downwind fallout was seaward, with considerable centralized fallout in Staten Island, Brooklyn, Queens, and western Long Island areas.

2. WASHINGTON, D.C. AREA

NATURE OF TARGET: Urban area.

TYPE/YIELD OF SOVIET WEAPON: Missile-delivered thermonuclear warhead in 9–10 MT range.

NUMBER OF WARHEADS DELIVERED: Six warheads with possible unknown number of other nondetonating weapons.

BURST TYPE: Airburst and groundburst.

SPECIAL FEATURES: Same as 1 above.

FALLOUT PATTERN: Prevailing winds created a fallout pattern that was generally easterly with some deflection SSE. Because of Washington’s unique location, most fallout was into Maryland, and secondarily into Delaware and western New Jersey.

3. SAN ANTONIO, TEXAS AREA

NATURE OF TARGET: Urban area.

TYPE/YIELD OF SOVIET WEAPON: Missile-delivered thermonuclear warhead in 9–10 MT range.

NUMBER OF WARHEADS DELIVERED: Three.

BURST TYPE: Airburst and groundburst.

SPECIAL FEATURES: Same as 1 above.

FALLOUT PATTERN: A frontal system was developing winds of 10–15 knots in a SE direction. Fallout was into South and East Texas, including the Houston area.

4. GREAT FALLS, MONTANA AREA

NATURE OF TARGET: U.S. Minuteman missile fields.

TYPE/YIELD OF SOVIET WEAPON: Missile-delivered thermonuclear warhead in 1–2 MT range.

NUMBER OF WARHEADS DELIVERED: Unknown, but estimated at 25+.

BURST TYPE: Groundburst for maximum silo destruction. Some airburst detonations.

SPECIAL FEATURES: Intense surface radiation, with moderate to severe atmospheric fallout downwind.

FALLOUT PATTERN: Winds for late October were SE. Because of the attack nature, initial radioactivity was widespread over a large area. Radiation extended to Wyoming and South Dakota.

5. GRAND FORKS, NORTH DAKOTA AREA

NATURE OF TARGET: U.S. Minuteman missile fields.

TYPE/YIELD OF SOVIET WEAPON: Missile-delivered thermonuclear warhead in 1–2 MT range.

NUMBER OF WARHEADS DELIVERED: Unknown, but estimated at 25+.

BURST TYPE: Groundburst for maximum silo destruction. Some airburst detonations.

SPECIAL FEATURES: Same as 4 above.

FALLOUT PATTERN: Winds were SE, hence fallout pattern developed over Minnesota, with some low-level fallout in Wisconsin.

6. MINOT, NORTH DAKOTA AREA

NATURE OF TARGET: U.S. Minuteman missile fields.

TYPE/YIELD OF SOVIET WEAPON: Missile-delivered thermonuclear warhead in 1–2 MT range.

NUMBER OF WARHEADS DELIVERED: Unknown, but estimated at 45+.

BURST TYPE: Groundburst for maximum depth destruction. Some airburst detonations.

SPECIAL FEATURES: Same as 4 above.

FALLOUT PATTERN: Winds were SSE-S for attack date. Early fallout was concentrated in N. Dakota, with some fallout in S. Dakota and minor fallout in Iowa.

7. RAPID CITY, SOUTH DAKOTA AREA

NATURE OF TARGET: U.S. Minuteman missile fields.

TYPE/YIELD OF SOVIET WEAPON: Missile-delivered thermonuclear warhead in 1–2 MT range.

NUMBER OF WARHEADS DELIVERED: Unknown, but estimated at 35+.

BURST TYPE: Groundburst for maximum depth destruction. Some airburst detonations.

SPECIAL FEATURES: Same as 4 above.

FALLOUT PATTERN: Winds were SSE. Fallout line was largely into S. Dakota and Nebraska, with development into Iowa and Missouri.

8. CHEYENNE, WYOMING AREA

NATURE OF TARGET: U.S. Minuteman and MX missile fields.

TYPE/YIELD OF SOVIET WEAPON: Missile-delivered thermonuclear warhead in 1–2 MT range.

NUMBER OF WARHEADS DELIVERED: Unknown but estimated at 35+.

BURST TYPE: Groundburst for maximum depth destruction. Some airburst detonations.

SPECIAL FEATURES: Same as 4 above.

FALLOUT PATTERN: Winds were SSE. Primary fallout occurred in Wyoming, Kansas, Colorado, and Nebraska, with some development Into southeastern Missouri.

ATTACHMENT ONE

LIST OF MAJOR FALLOUT DATA COLLECTION CENTERS

(Manned and Remote)

MONTANA

Billings	45D 48M North / 108D 32M West
Glasgow	48D 13M North / 106D 37M West
Great Falls	47D 29M North / 111D 22M West
Havre	48D 33M North / 109D 46M West
Helena	46D 36M North / 112D 00M West
Kalispell	48D 18M North / 114S 16M West
Miles City	46D 26M North / 105D 52M West
Missoula	46D 55M North / 114D 05M West

NEW YORK

Central Park/Manhattan	40D 47M North / 78D 58M West
Kennedy Airport	40D 39M North / 73D 47M West
La Guardia Airport	40D 46M North / 73D 54M West

NORTH DAKOTA

Bismarck	46D 46M North / 100D 45M West
Fargo	46D 54M North / 96D 46M West
Williston	48D 11M North / 103D 38M West

SOUTH DAKOTA

Aberdeen	45D 27M North / 98D 26M West
Huron	44D 23M North / 98D 13M West
Rapid City	44D 03M North / 104D 04M West
Sioux Falls	43D 34M North / 96D 44M West

TEXAS

Austin	30D 18M North / 97D 42M West
Corpus Christi	27D 46M North / 97D 30M West
Houston	29D 58M North / 95D 21M West
San Antonio	29D 32M North / 98D 28M West

WASHINGTON, D.C.

Dulles Airport	38D 57M North / 77D 27M West
National Airport	38D 51M North / 77D 02M West

WYOMING

Casper	42D 55M North / 106D 28M West
Cheyenne	41D 09M North / 104D 49M West
Lander	42D 49M North / 108D 44M West
Sheridan	44D 46M North / 106D 58M West

ATTACHMENT TWO

BRIEF DESCRIPTION OF RADIOACTIVE FALLOUT

Radioactive fallout is created by thermonuclear weapons as a result of residual radiation, that is, radiation that occurs or is induced in particulate matter approximately one minute after detonation. In thermonuclear weapons especially, large numbers of high-energy neutrons are produced, which interact with elements in the air and on the ground; these elements then become radioactive and in turn emit beta and gamma radiation.

Fallout may be considered of two kinds: early and delayed. Early fallout occurs within 24 hours and is the most severe. Fallout of this type produces contamination and presents a biologic hazard. Delayed fallout produces very fine particles of radiated material that are spread in the atmosphere. The hazard with delayed fallout is long term, especially because of elements with very long half-lives, such as cesium 137 and strontium 90.

Airbursts are more likely to produce delayed fallout because of the height of detonation. Surface bursts, conversely, produce fallout that is more localized but more intense.

Radioactive particles generally vary in size from 1 micron to several millimeters. The larger particles tend to fall within 24 hours and are the most radioactive. Between 50 and 70 percent of total radioactivity is produced as early fallout.

Weapons can be made to produce larger amounts of radioactive elements, hence the term “dirty weapons.” This is done by using all-fission warheads or by enhancing thermonuclear weapons with additional fission steps, in addition, thermonuclear weapons can be wrapped in tungsten or cobalt casings.

Fallout is carried by winds and is affected by altitude, moisture content of air, etc. A 10 MT surface weapon, for example, can, on detonation, rise to a height of 80000 feet, thus introducing radioactive particles into airstreams that circle the earth. More localized fallout is subject to geographical contour, nature of burst, and other factors that make statistical predictability unreliable.