III.OPERATIONAL USE AND LIMITATIONS
A. CPE Wear Time
CPE components are rated for how long they provide fullprotection in both contaminated and non-contaminatedenvironments. For example, in a contaminated environment, theChemical Protective Overgarment (CPOG) is rated for up to sixhours of protection and the Battledress Overgarment (BDO) for 24hours.[31] Overgarments actually exposedto chemical warfare agents are never worn again.
In a non-contaminated environment, the CPOG gradually beginsto lose protection after 14 days of almost full time wear, whilethe BDO can last 30 days. Returning the garments to theirvapor-seal bags "stops the clock" on these wearperiods.[32] The bag protects theovergarment from the degrading effects of such things asmoisture, smoke, fuel solvent vapors, and sunlight.[33] Over time, extensively wornovergarments can also become unserviceable because the charcoalmigrates to the end of the sleeves and trousers, or the knees andelbows wear out, or the garment is exposed to too much mud anddirt.[34] Because of the limitedavailability in the Gulf of replacement CPE, commands wereflexible about wear time in a non-contaminated environment underCW threat. It was decided that wearing an overgarment beyond theestablished full protection limits would put troops at less riskthan being exposed to chemical warfare agents without sufficientreplacement protective gear.[35]
B.Performance Degradation Caused by CPE Wear
Depending on the outside temperature and the physical level ofwork, MOPP postures above Level 0 can result in the followingindividual performance limitations:[36]
In recent years, the impacts of these kinds of effects (atMOPP Level 4) on combat operations have been studied extensivelyin Army field exercises. The following is a compendium ofobservations taken from reports on these studies:
- In a variety of tasks, degradation is 20 to 50 percent.[39]
- Oxygen consumption increases about 10 percent in full CPE compared to light clothes.[40] This indicates that personnel in MOPP-4 expend more energy than personnel in MOPP-0 performing the same tasks.
- Reduced sensory awareness makes it harder to stay awake when tired.[41]
- Soldiers require 1.5 to 3 times longer to perform tasks requiring manual dexterity in MOPP-4 than without CPE.[42]
- Performing a task for the first time takes about 30 percent longer.[43]
- Troops tend to omit or poorly complete certain tasks (such as camouflage and support activities).[44]
- Some cognitive tasks, like encoding, suffer a performance loss of nearly 23 percent in MOPP-4.[45]
- Leader performance declines: they become exhausted, sleep less, become disoriented or lost, get irritable, and delegate less. Leaders often are the first MOPP casualties.[46]
- Unit movement formations bunch up to help leaders maintain control.[47]
- When platoon leaders become casualties, it takes four times as long for a platoon to realize it is leaderless. The next senior soldier assumes command 85% less often than in non-CPE exercises.[48]
- NBC Overboots provide poor footing on hilly terrain, on loose ground, or in rain.[49]
- NBC garments absorb rain and become very heavy and cumbersome.[50]
- Rifle marksmanship drops about 15 to 19 percent for soldiers in MOPP-4.[51]
- Individual weapon firing rates decrease 20 percent in the defense and 40 percent in the attack. It takes twice as long to complete an attack, and nearly twice as many soldiers are required for success.[52]
- The proportion of enemy personnel engaged decreases by one-third.[53]
- Weapon crews use terrain much less effectively for cover and concealment, and the number of casualties suffered per enemy defender killed increases by 75 percent.[54]
- Shots fired at friendly instead of enemy soldiers increases from 5 to almost 20 percent.[55]
- Platoons call for three times more indirect fire (e.g., artillery). Indirect fire becomes more effective than individual weapons in inflicting casualties on the enemy.[56]
- Land navigation is seriously degraded, particularly at night.[57]
- Night vision devices cannot be used while masked.[58]
- Radio communication is difficult because of reduced clarity and volume.[59] Speaking through the voicemitter makes the speaker sound brassy and muffled, and consonants become indistinct. The hood and background noise (breathing, garment movement, etc.) degrades hearing.[60]
- Communications are only about half as effective as in a non-CPE environment. Total time spent on radio traffic more than doubles. The number and length of radio transmissions rises by 50 percent.[61]
- Logistics operations take longer and can become confused.[62]
- Maintenance takes longer. Recovering armored vehicles takes up to 20 percent more time; repairing weapons takes up to 70 percent more time.[63]
Training for key combat tasks in CPE can reduce suchperformance degradation.
C. MOPP Level Analysis
Depending on the tactical situation, commanders choose theappropriate MOPP level. Before making a decision, the commandermust address the following issues: [64]
- Nature of the mission (offensive or defensive)
- Likelihood of CW use and what agents might be used
- Likely friendly targets
- Expected warning time
- Additional available protection (shelter or cover)
- Physical demands of the projected work
- Mental demands of the projected work
- Speed required for mission accomplishment
- Expected duration of the mission
- Likely follow-on mission
- Whether adequate water and food supplies are available
Commanders must also consider other factors when setting theMOPP level. For example, the most likely time for a chemicalattack is between late evening and early morning, when agentvapor tends to linger close to the ground. In the heat of theday, agents rise rapidly in unstable air.[65]
D. CommandersGuidance
Commanders should use MOPP flexibly to protect their forces ina potential or actual Chemical Warfare situation. While thevarious headquarters provide initial directives on MOPP level,subordinate units often adapt this guidance to local conditionswhen warranted (although a commander generally sets a minimumMOPP level). Units can increase the MOPP level set by higherheadquarters in response to direct threats.[66]
Because Gulf War commanders often had to use their ownjudgment in setting MOPP levels, different units experienceddifferent degrees of CPE wear under similar circumstances. Forexample, after the first 24 hours of the ground war, thecommander of the 2d Marine Division had his forces take off theirCPE. In the adjacent 1st Marine Division sector, Marinescontinued to wear some of their CPE throughout the groundoffensive.[67]
E. Reducing MOPPLevel and Unmasking
Commanders downgrade the MOPP level as the threat decreases.Before a unit unmasks in a potential chemical threat area, theunits chemical detection equipment must determine if achemical hazard exists. If such tests are negative, the next stepis "selective unmasking." Figure4 diagrams the process.
Figure 4. SelectiveUnmasking Process[68]
The M256 kit is the most sensitive vapor detection gear. If aunit must use a less sensitive test for an initial contaminationcheck, full unit unmasking requires at least two limitedunmaskings to confirm no contamination. First, one or twodesignated troops hold their breath, unmask for 15 seconds withtheir eyes open, and then remask. Others then observe their eyesfor contraction of the pupils (miosis), the first sign ofexposure to nerve agent vapor. If those who unmasked show nosymptoms, they remove their masks and breathe normally for fiveminutes and remask while being observed for symptoms. If nosymptoms appear, an all clear is sounded and the remaining troopsof the unit unmask. When the sensitive M256 kit confirms nocontamination, the procedure skips the first step involving eyeexposure without breathing. All selective unmasking involvescareful observation of the designated troops and immediatereadiness to administer antidotes in response to any sign oftoxic reaction.[69]
Procedures established for some Army units in the Gulfincluded an extra selective unmasking step after unmasking for 15seconds without breathing. This step, used where no detectionequipment was available, involved unmasking and taking two orthree breaths and remasking for an additional 10 minutes ofobservation. If no symptoms appeared, the same soldiers unmaskedfor five minutes.[70]
F. Automatic Masking
In addition to establishing the MOPP Level, commanders set theguidance for automatic masking. Automatic masking means that nomatter what the command-established MOPP Level, militarypersonnel are expected to rapidly don masks if there is animmediate threat. For example, automatic masking could occurunder any of the following conditions:[71]
- An automatic chemical agent alarm sounds.
- A chemical agent detector paper reads positive.
- Troops experience symptoms of a chemical agent exposure.
G. Threat Level Color Codes
Some US Air Force and Marine units in Operation Desert Stormused color codes to supplement MOPP levels. These codes generallyreferred to the immediacy of the chemical threat. TheMarines system included the following:[72]
- "White." Enemy forces have the capability to employ NBC weapons, but attack is not probable at this time.
- "Yellow." Attack probable, units maintain MOPP-0.
- "Red." Siren sounds. Attack is imminent. Units go to MOPP-4.
- "Black." Siren sounds. Friendly forces nearby have been attacked with CW. Units remain in MOPP-4 until "all clear" is given.
The Air Force had a similar system, with stages defineddifferently:[73]
- "All Clear." Normal Operations. Have Chemical Protective Equipment (CPE) and field gear readily available.
- "Alert Yellow." Attack is probable. Wear CPE and field gear as directed.
- "Alert Red." Attack is imminent or in progress. Don protective equipment (to include field gear) and take cover.
- "Alert Black." NBC contamination is suspected or actual. Wear full chemical protective ensemble and field gear.
An Air Force daily log for Al Kharj Air Force Base, SaudiArabia included this entry for January 21,1991:
"At 2200 hours the air base went on a Red Alert, MOP[P] Level IV. Personnel were warned to take cover but the alert was called off after a short period of time. Al Kharj Air Base was then put on a Yellow Alert, MOP[P] Level II which meant that people, for the second time in three nights, had to sleep in their chemical warfare gear."[74]
In late January, after SCUD missile attacks failed to includechemical warheads (and a need to conserve scarce overgarmentsbecame clear), the Air Force instituted MOPP Level ALPHA. Thisinvolved taking cover in a hallway or bunker, donning the mask,hood, and gloves, and ensuring full body coverage with long pantsand long-sleeved shirts; no NBC overgarments were donned. If anattack actually ensued, ALARM BLACK MOPP ALPHA was to bedeclared. The overgarments, however, were to be left packed andat hand unless a chemical agent was actually detected. In thatevent, ALARM BLACK MOPP 4 would be issued and the overgarmentswould be donned.[75]
Despite these variations, the standard MOPP level system wasthe primary way of tying protection level to chemical agentthreat for the majority of US forces during the Gulf War.[76]
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