Level A protection

Because of the extreme dermal hazard posed by vesicants, responders should wear a Level A protective ensemble whenever there is a potential for exposure to any solid or liquid agent, or to an elevated or unknown concentration of agent vapor. 

Use only chemical protective clothing that has undergone material and construction performance testing against carbon monoxide and metal carbonyls. If the concentration of vapor exceeds the level necessary to produce effects through dermal exposure, then responders should wear a Level A protective ensemble. 

If an aerosol generating device is employed (e.g., sprayer), or the dissemination method is unknown and the release is ongoing, then responders should wear a Level A protective ensemble. Once the device has stopped generating the aerosol or has been rendered inoperable, and the aerosol has settled, then responders can downgrade to Level B. 

Level A protection should be worn when the highest level of respiratory, skin, eye, and mucous membrane protection is needed. This level consists of a fully-encapsulated, vapor-tight, chemical-resistant suit, chemical-resistant boots with steel toe and shank, chemical-resistant inner/outer gloves, coveralls, hard hat, and self-contained (positive pressure) and SCBA. 

Responders should use NIOSH-approved, pressure-demand SCBA in conjunction with Level A protective suit in responding to a suspected biological incident where any of the following information is unknown or the event is uncontrolled ... 

Fire Tabun reacts with steam and water to produce toxic and corrosive vapors. Any personnel not fighting a fire of sarin should immediately be evacuated from the area. Respiratory protection is required (positive pressure, full face piece, NIOSH-approved SCBA will be worn). When response personnel respond to handle rescue or reconnaissance, they will wear Level A protection that should be worn when the highest level of respiratory, skin, eye, and mucous membrane protection is needed. This level consists of a fully-encapsulated, vapor-tight, chemical-resistant suit, chemical-resistant boots with steel toe and shank, chemical-resistant inner/outer gloves (butyl rubber glove M3 and M4 Norton, chemical protective glove set), coveralls, hard hat, and self-contained (positive pressure) breathing apparatus (SCBA). 

Note When DPE or TAPES is not available the M9 or M40 series mask with Level A protective ensemble can be used. However, use time shall be restricted to the extent operationally feasible, and may not exceed one hour. 

Level A protection is a totally encapsulating protective cocoon. The garment s material is totally impermeable to both vapor and liquid. Although the garment has seams and a zipper, both of these... 

Spill-area-limitation devices (personnel wearing flash suits over Level A protective clothing)... 

There are some issues that are unique to chemical weapons. Certainly, most contain an explosive charge and possibly an initiating explosive or fuse. However, some CWM may be stored in glass containers, making location difficult. Also, CWM residuals may exist in the soil and pose a hazard to excavation crews. UXO teclmicians clearing possible CWM sites should always wear respirators, if not Level A protective suits. 

CFR1910.120(g)(3)(iv) 4.5.3 Totally-encapsulating chemical protective suits (protection equivalent to Level A protection as recommended in Appendix B of 29CFR1910.120) shall be used in conditions where skin absorption of a hazardous substance may result in a substantial possibility of immediate death, immediate serious illness or injury, or impair the ability to escape. 

Level B is used when full respiratory protection is required but danger to the skin from vapor is less. It differs from Level A in that it incorporates a nonecapsulating, splash-protective, chemical-resistant suit (splash suit) that provides Level A protection against liquids, but is not airtight. 

When would Level A protection be worn What follows is a partial list of conditions that warrant suiting up in PPE to Level A protection. 

---