A. CPE Wear Time

CPE components are rated for how long they provide full protection in both contaminated and non-contaminated environments. For example, in a contaminated environment, the Chemical Protective Overgarment (CPOG) is rated for up to six hours of protection and the Battledress Overgarment (BDO) for 24 hours.[31] Overgarments actually exposed to chemical warfare agents are never worn again.

In a non-contaminated environment, the CPOG gradually begins to lose protection after 14 days of almost full time wear, while the BDO can last 30 days. Returning the garments to their vapor-seal bags "stops the clock" on these wear periods.[32] The bag protects the overgarment from the degrading effects of such things as moisture, smoke, fuel solvent vapors, and sunlight.[33] Over time, extensively worn overgarments can also become unserviceable because the charcoal migrates to the end of the sleeves and trousers, or the knees and elbows wear out, or the garment is exposed to too much mud and dirt.[34] Because of the limited availability in the Gulf of replacement CPE, commands were flexible about wear time in a non-contaminated environment under CW threat. It was decided that wearing an overgarment beyond the established full protection limits would put troops at less risk than being exposed to chemical warfare agents without sufficient replacement protective gear.[35]

B. Performance Degradation Caused by CPE Wear

Depending on the outside temperature and the physical level of work, MOPP postures above Level 0 can result in the following individual performance limitations:[36]

In recent years, the impacts of these kinds of effects (at MOPP Level 4) on combat operations have been studied extensively in Army field exercises. The following is a compendium of observations taken from reports on these studies:

Training for key combat tasks in CPE can reduce such performance degradation.

C. MOPP Level Analysis

Depending on the tactical situation, commanders choose the appropriate MOPP level. Before making a decision, the commander must address the following issues: [64]

Commanders must also consider other factors when setting the MOPP level. For example, the most likely time for a chemical attack is between late evening and early morning, when agent vapor tends to linger close to the ground. In the heat of the day, agents rise rapidly in unstable air.[65]

D. Commander’s Guidance

Commanders should use MOPP flexibly to protect their forces in a potential or actual Chemical Warfare situation. While the various headquarters provide initial directives on MOPP level, subordinate units often adapt this guidance to local conditions when warranted (although a commander generally sets a minimum MOPP level). Units can increase the MOPP level set by higher headquarters in response to direct threats.[66]

Because Gulf War commanders often had to use their own judgment in setting MOPP levels, different units experienced different degrees of CPE wear under similar circumstances. For example, after the first 24 hours of the ground war, the commander of the 2d Marine Division had his forces take off their CPE. In the adjacent 1st Marine Division sector, Marines continued to wear some of their CPE throughout the ground offensive.[67]

E. Reducing MOPP Level and Unmasking

Commanders downgrade the MOPP level as the threat decreases. Before a unit unmasks in a potential chemical threat area, the unit’s chemical detection equipment must determine if a chemical hazard exists. If such tests are negative, the next step is "selective unmasking." Figure 4 diagrams the process.

Figure 4. Selective Unmasking Process[68]

The M256 kit is the most sensitive vapor detection gear. If a unit must use a less sensitive test for an initial contamination check, full unit unmasking requires at least two limited unmaskings to confirm no contamination. First, one or two designated troops hold their breath, unmask for 15 seconds with their eyes open, and then remask. Others then observe their eyes for contraction of the pupils (miosis), the first sign of exposure to nerve agent vapor. If those who unmasked show no symptoms, they remove their masks and breathe normally for five minutes and remask while being observed for symptoms. If no symptoms appear, an all clear is sounded and the remaining troops of the unit unmask. When the sensitive M256 kit confirms no contamination, the procedure skips the first step involving eye exposure without breathing. All selective unmasking involves careful observation of the designated troops and immediate readiness to administer antidotes in response to any sign of toxic reaction.[69]

Procedures established for some Army units in the Gulf included an extra selective unmasking step after unmasking for 15 seconds without breathing. This step, used where no detection equipment was available, involved unmasking and taking two or three breaths and remasking for an additional 10 minutes of observation. If no symptoms appeared, the same soldiers unmasked for five minutes.[70]

F. Automatic Masking

In addition to establishing the MOPP Level, commanders set the guidance for automatic masking. Automatic masking means that no matter what the command-established MOPP Level, military personnel are expected to rapidly don masks if there is an immediate threat. For example, automatic masking could occur under any of the following conditions:[71]

G. Threat Level Color Codes

Some US Air Force and Marine units in Operation Desert Storm used color codes to supplement MOPP levels. These codes generally referred to the immediacy of the chemical threat. The Marines’ system included the following:[72]

The Air Force had a similar system, with stages defined differently:[73]

An Air Force daily log for Al Kharj Air Force Base, Saudi Arabia 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 include chemical warheads (and a need to conserve scarce overgarments became clear), the Air Force instituted MOPP Level ALPHA. This involved taking cover in a hallway or bunker, donning the mask, hood, and gloves, and ensuring full body coverage with long pants and long-sleeved shirts; no NBC overgarments were donned. If an attack actually ensued, ALARM BLACK MOPP ALPHA was to be declared. The overgarments, however, were to be left packed and at hand unless a chemical agent was actually detected. In that event, ALARM BLACK MOPP 4 would be issued and the overgarments would be donned.[75]

Despite these variations, the standard MOPP level system was the primary way of tying protection level to chemical agent threat for the majority of US forces during the Gulf War.[76]


| First Page | Prev Page | Next Page |