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II. TECHNICAL CHARACTERISTICS

A. Chemical Protective Equipment (CPE) Components

The key parts of CPE include:

  • Overgarment. US forces in the Gulf War had several models of overgarment. (If exposed to contamination, the wearer discarded and replaced overgarments. They were not decontaminated or recycled. Troops normally wore the overgarment over the field uniform, but it could be worn over only underwear to reduce heat buildup.)[7]
  • The Battledress Overgarment (BDO) consisted of a coat and trousers in olive drab or camouflage pattern. The BDO has an outer cotton layer and an inner layer of charcoal impregnated polyurethane foam. It is permeable, permitting some air to filter in and out—thereby reducing heat buildup, while absorbing and trapping any chemical agents coming in contact with the BDO.
  • Many troops in Operation Desert Shield deployed with the Chemical Protective Overgarment (CPOG), similar in construction to the BDO, but older in design. It is solid olive drab with an outer layer of nylon cotton and charcoal impregnated foam inside.
  • Army aircrews wore the Aircrew Uniform Integrated Battlefield (AUIB) instead of a normal flight suit or the BDO/CPOG. It protects against both chemical hazards and fire and includes features specialized for use in the cockpit.[8]
  • Marines had four different chemical protective suits: the Marine Corps Standard Protective Overgarment (OG84), the Navy Lightweight Suit (MKIII), the Aviators Chemical Ensemble, and the British Lightweight Suit (MK IV).
  • Air Force aircrews also wore the British Mark IV Lightweight Suit (MK IV).
  • Chemical Protective Helmet Cover. This cover protects against chemical and biological contamination and is made from butyl-coated nylon cloth. It has an elastic web in the hem to gather the cover and hold it on the helmet.[9]
  • Vinyl Overboot. Worn over combat boots, the impermeable overboot protects against chemical, radiological, and biological hazards as well as rain, mud, or snow. If contaminated, decontamination can return them to service.[10]
  • Protective Masks. Several models of protective masks were used by the US military in the Gulf War. All the masks protect the face and airways from airborne contamination by all known chemical or biological agents and radioactive dust. In the Gulf War, most US troops in dismounted ground operations had the M17 Series Protective Mask.[11] Some troops had the newly fielded M40 Protective Mask. Both masks have similar basic functions and levels of protection, but the M40 is more comfortable, with improved convenience and voice transmission. They both include a binocular lens system, elastic head harness, voicemitters, and filters to trap NBC contaminants. The M17 Series is made of butyl rubber while the M40 facepiece is made of silicone with a second skin which is made of butyl rubber. Masks that could be connected to vehicle air filtration systems were issued to tank crews (M25) and aircrews (M24).[12] The Air Force ground personnel used the M17 Series Masks or the MCU-2/P series masks. The MCU-2/P is similar to the M40 except that it has a single large eye lens instead of two.
  • Field Protective Hood. The hood attaches to and is donned with the mask. It protects the head and neck from chemical agents and other NBC hazards.[13]
  • Chemical Protective Glove Set. The glove set includes outer gloves made of impermeable butyl rubber and inner gloves made of thin cotton to absorb moisture.[14] The outer gloves come in three thicknesses:
  • The 7 mil gloves are used by medical personnel, teletype operators, electronic repair personnel, etc., who need high touch sensitivity and who normally will not expose the gloves to harsh treatment.
  • The 14 mil gloves are used by aviators, vehicle mechanics, and weapon crews needing some touch sensitivity but who also are unlikely to give the gloves harsh treatment.
  • The 25 mil gloves are used by troops who perform close combat tasks and other heavy labor.
  • Auxiliary Equipment. Skin decontamination kits, antidote kits, and M8/M9 chemical agent detector paper also accompany the protective clothing as auxiliary equipment.[15, 16]

B. How CPE Protects Against Chemical Weapons (CW)

Before discussing how CPE is used in the field, it is useful to understand the types of chemical weapons it protects against and how. Chemical warfare agents may be delivered in various forms, including gas, liquid, or aerosol. They can be non-persistent (lasting for only minutes) or persistent (remaining effective for weeks). Chemical agent clouds can cover large areas and drift into foxholes, hatches, and bunkers to cause casualties.[17] Table 1 summarizes chemical warfare agent characteristics. Chemical Protective Equipment is designed to protect against both persistent and non-persistent agents.

 

Table 1. Types and Characteristics of Chemical Agents.[18]

Types of
Agents
Symbol Persistence Rate of
Action
[19]
Entrance
Summer Winter Vapor/Aerosol Liquid
Nerve G-Agents 10 min to 24 hours 2 hr to 3 days Very Quick Eyes, Lungs Eyes, Skin, Mouth
V-Agents 2 days to 1 week 2 days to weeks Quick Eyes, Lungs Eyes, Skin, Mouth
Choking CG, DP 1 to 10 min 10 min to 1 hr Slow Lungs Eyes
Blister HD,HN 3 days to 1 week Weeks Slow Eyes, Skin, Lungs Eyes
L 1 to 3 days Weeks Quick Eyes, Skin, Lungs Eyes, Skin, Mouth
CX Days Days Very Quick Lungs Eyes, Skin, Mouth
Blood AC, CK 1 to 10 min 10 min to 1 hr Very Quick Lungs Eyes, Injured Skin

 

The special filters in the protective masks absorb airborne agents and protect the lungs and eyes. The other components of CPE protect against agent contact with the skin—regardless of whether it comes in solid, liquid, or vapor form.[20] The overboots and butyl rubber gloves are impermeable and provide a solid barrier to liquid agents. A solid barrier for the rest of the body is not practical for most combat functions because it would cause the rapid buildup of body heat and moisture. Overgarments and hoods permit some passage of air and moisture through two layers, allowing perspiration to evaporate. The outer layer limits liquid absorption or redistributes it to reduce concentration. An inner layer filters the air and any vapor that penetrates the outer layer. This inner layer of charcoal-impregnated foam acts like the filter in the protective mask. Charcoal is highly porous and able to absorb liquid, gas, and aerosol agents.[21] If mask filters or permeable protective garments become exposed to a chemical agent, they are discarded (and properly disposed of) after wear and then replaced, in accordance with each service’s doctrine. For example, the Air Force chooses to air out vapor-contaminated CPE in a toxic free area, and then reuse them. Impermeable gloves and overboots can be decontaminated and recycled for use.[22]

Troops potentially exposed to high concentrations of chemical warfare agents (e.g., decontamination crews) receive special impermeable overgarments.[23]

C. CPE Related to MOPP Levels

Figure 2 shows the CPE prescribed for the five MOPP levels:

MOPP-0 MOPP-1 MOPP-2 MOPP-3 MOPP-4

Figure 2. CPE Worn at Each MOPP Level.[24], [25]

Table 2 provides more detail on standard MOPP Level procedures.

Table 2. Wear of CPE by MOPP Level.[26]

EQUIPMENT

MOPP 0

MOPP1

MOPP2

MOPP3

MOPP4

Overgarment and Helmet Cover

Available[27]

Worn

Worn

Worn

Worn

Vinyl Overboot

Available

Available

Worn

Worn

Worn

Mask and Hood

Carried

Carried

Carried

Worn

Worn

Gloves

Available

Carried

Carried

Carried

Worn

 

While in buildings and vehicles that offer some protection against liquid agents, troops may operate in a modified MOPP posture to protect against vapor threats. Some vehicles (such as the M1A1 Abrams Tank) have air pumped in through filters (overpressure systems), permitting a mask-free operation in contaminated terrain.[28] Troops assume the MOPP level set by the commander when they exit these special environments.

To maintain effectiveness in MOPP Levels 3 or 4, commanders can declare "MOPP Open." This permits troops to open the jacket and roll up the hood to improve ventilation for a limited period of time based on estimates of the chemical threat.[29]

D. Donning Time for CPE

As troops put on more protective clothing and equipment, and the MOPP level continues to increase, the time required to achieve the higher levels of protection decreases. For example, increasing the MOPP level from MOPP Level 0 to MOPP Level 1 cuts the incremental time to go to MOPP-4 in half (from eight to four minutes). Increasing the MOPP level from MOPP-1 to MOPP-2 cuts the time to go to MOPP-4 from four minutes to under a minute. Figure 3 shows the amount of time necessary to attain MOPP-4 from each lower MOPP Level.

Figure 3. MOPP Level and Time to Go to MOPP-4.[30]

 


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