BIOLOGICAL 

The many variables, involved in estimating persistency of biological hazards, require separate consideration for each instance of contamination. Specially trained medical personnel will consider specific treatment direction only after the contamination has been specifically identified. For example, biological agents will persist longer in cold weather. Temperate inversions (stable conditions) that exist over snowfields also tend to prolong the stay of an aeorsolized biological cloud.

RADIOLOGICAL 

A general idea of the persistency of radiological hazards can be gained by taking radiation dose readings. At this time, the NCF uses two types of radioactive detection and computation (RADIAC) instruments:

1. The AN/ PDR-27 instrument provides radioactivity detection in the lower ranges. It is designed to detect beta radiation and measure and detect gamma nuclear radiation. The AN/ PDR-27 is also used to monitor low level radiation contamination on personnel, supplies, and equipment.

2. AN/ PDR-43 instrument provides detection of radioactivity in the high range. It is designed to detect beta radiation and measure and detect gamma nuclear radiation.

NOTE: Only qualified personnel are authorized to operate RADIAC instruments.

For operational purposes, you can use the "7-10 rule of thumb" to estimate future radiation levels. This rule provides a general estimate and should be used for planning only. The rate of radioactive decay is proportional over time. The 7-10 rule means that for seven multiples of time after the burst, the radiation intensity will decrease by a factor of 10. For example, if 2 hours after the burst your radiation reading is

100 Centigray (cGy) (rad) per hour, then 14 hours after the burst (7 times 2 hours), you can expect a reading of about 10 cGy (100 cGy divided by 10). Radiation contamination is not affected by climatic conditions or other variables that affect chemical contamination. The Army manual, FM 3-3-1, describes radiation decay rates in detail.

NEGLIGIBLE RISK

You must consider decon if the levels of contamination exceed negligible risk levels.

BIOLOGICAL AND CHEMICAL 

Negligible risk levels for biological and chemical contamination are contamination that will cause mild incapacitation among no more than 5 percent of unprotected troops operating for 12 continuous hours within 1 meter of contaminated surfaces. Measurements that determine safe levels are made with detection equipment held 1 inch away from the surface. For example, a one bar reading displayed on the chemical agent reduced hazard level negligible risk level.

RADIOLOGICAL

monitor (CAM) indicates a that should be considered as a Negligible risk levels for radiological contamination are measurements of 0.33 centigray (cGy) or less. This level of radiation will cause no more than 2.5 percent mild incapacitation to unprotected troops.

CONTAMINATION COMBINATIONS 

Simultaneous enemy CBR attacks will probably be part of the strategy of the enemy. Risk assessments include consideration that the enemy may use combinations of nuclear, biological, and chemical weapons or may use any of these combined with conventional fire. Once CBR weapons have been introduced on the battlefield, the enemy may try to deceive you regarding the type of hazard.

The thermal effects of a nuclear blast might destroy the effects of any chemical or biological weapons used simultaneously. However, chemical or biological weapons effectiveness is increased if used following a nuclear attack. Nuclear blast casualties and psychologically stressed troops are vulnerable to a CBR agent attack. Agents could enter collective protective shelters, communication facilities, and vehicles damaged by the nuclear detonation.

When CBR contamination hazards exist, decontaminate the chemical agents first. Chemical agents are normally the most lethal and fastest acting type of contamination. The decon methods for chemical agents are also effective for neutralizing or removing biological and radiological contamination. The reverse is not true.

The enemy may use a mixture of agents in their munitions to cause multiple types of contamination. Such mixtures could be used to achieve the following various purposes:

1. Lower the freezing point of the agents and increase agent persistency, such as mustard lewisite mixture.

2. Create both percutaneous (through the skin) and inhalation hazards, such as thickened GD and GB.

3. Complicate agent identification of mixed agents, making treatment of casualties more difficult.

4. Combine agents with both immediate and long-term persistency, such as anthrax, with an incubation period of 1 to 5 days and histoplasmosis (pulmonary infection disease) with an incubation period of 5 to 18 days.

There is no field detecting system that can detect or identify biological agents. Therefore, combinations of biological and chemical contaminants present a different challenge. This challenge can be dealt with if standard chemical decon measures are followed at once. Use standard chemical decontaminants when combinations are known or suspected to exist. They can be used for toxins and biological agents as well as chemical agents. See appendix IV for a description of field expedient chemical decontaminants for use against these hazards.

Do not base decon measures solely upon the first hazard identified. Make sure you check thoroughly to identify all agent hazards. When specific agents are detected, take appropriate decon measures.

REASONS FOR DECON 

You must have a good idea of the reasons for decon and the types/ techniques of decon. You must assess your tactical situation and consider your decon resources within the context of mission, enemy, terrain, troops, and time available (METT-T). You must know the principles of decon and know how decon affects your combat power. Protective clothing and equipment (MOPP gear) and collective protection shelters offer only a temporary solution. Decon is a more permanent solution because it includes the removal, the destruction, or the neutralization of contamination. When you have become contaminated, there are practical reasons why at least some decon must occur as soon as possible. You must use these decon concepts in selecting the best action to take to accomplish your mission.

Decon should be considered within the context of METT-T and resources available. The four factors that must be addressed before you decide to decontaminate are as follows:

Lethality Performance degradation

Equipment limitations Transfer and spread

LETHALITY

Some types of contamination are so toxic they can kill or incapacitate if they contact exposed skin for a few minutes. If your skin becomes contaminated, you must stop breathing, mask, give the alarm, and decontaminate your skin immediately. Periodically, observe for nerve agent symptoms if the agent type is unknown.

PERFORMANCE DEGRADATION

MOPP (mission-oriented protective posture) gear provides protection but also degrades performance. The longer you are in MOPP 4, the lower your efficiency. Using tools and weapons while wearing the protective gloves is awkward. The mask reduces your field of view, making it difficult to optical sights and night vision devices. use some Extended operations in MOPP gear tire and discourage troops. Troops cannot eat while wearing a mask. Urinating and defecating are potentially dangerous in a contaminated area. Even resting and sleeping are difficult because it is hard to breathe through the mask. Hot or humid climates compound these problems because the mask makes breathing more difficult.