(Photo by Spc. JD Sacharok)

For hundreds of years, humans have developed technologies that yield the maximum amount of enemy fatalities in efforts to protect the home front. As time progresses, so, too, do the methods military leaders use to strike fear into the hearts of their deadly opponents.

One such threat that dates back hundreds of years is that of a chemical attack that can strike in an instant and indiscriminately kill.


Chemical attacks were deployed on the battlefields of World War I and, although they're looked down on by much of today's international community, they can still be deployed at any time. Now more than ever, U.S. troops are trained to protect themselves from potential hazards using specialized gear. This gear is ranked by Mission Oriented Protective Posture (MOPP) levels, which ensure that troops have proper protection against any amount of chemical threat.

Marines and sailors with the 11th MEU's command element put their MOPP gear on during the 11th MEU's gas chamber training.(Photo by Lance Cpl. Demetrius Morgan)

MOPP levels range from zero to four. They're based on current chemical and biological threats and can elevate in minutes, so troops must always be prepared. Over garments, gas masks and hoods, boot covers, and gloves round out the gear necessary to protect troops.

Level 0

MOPP level zero is simply having all the gear stated above on-hand and ready to don. Though chemical threats are unlikely, they do exist and service members need to be ready.

MOPP level zero

Level 1

MOPP level one requires the troop to don over garments. This means a chemical threat is present, so troops must remain alert, as the hazard could escalate at any time.

MOPP level one.

Level 2

As the threat increases, so do MOPP levels. MOPP level two mandates that ground pounders quickly put on the both over garments and boot covers.

MOPP level two

Level 3

Moving on to MOPP level three. Service members must don over garments, a gas mask and hood, and boot covers. At this level, the threat of coming in contact with hazardous vapors is high.

MOPP level three

Level 4

Lastly, MOPP level four — which is, by far, the scariest of them all. This level requires over garments, gas masks and hoods, gloves, and boot covers to be worn as a chemical or biological threat is present in the area.

MOPP level four

To determine threat levels, troops use M9 paper, which can detect the presence of liquid chemical agents, like nerve agents. When this paper comes in contact with a harmful agent, it turns a reddish brown color. This tape is usually placed in well-occupied, highly visible areas for constant monitoring.