Chemical Agents - How to MOPP Up

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Chemical Agents - How to MOPP Up
by Sgt. Frank R. Santiago
Marine Corps News
January 31, 2003

MARINE CORPS RECRUIT DEPOT SAN DIEGO, Calif. -- Ever since the development of chemical, biological adn nuclear weapons, Marines have trained to protect themselves from its effects and carry on with the mission. Part one of this three-part series emphasizes the history, creation and symptms of exposure to agents used as weapons

* Chemical warfare began during World War I. On April 22, 1915, Germans used large amounts of chlorine gas, about 160 tons, which was released from 6,000 pressurized cylinders into the wind against the allies. The chlorine floated in huge clouds toward the allies until it reached the allied lines causing over 5,000 troop deaths and wounding more than 10,000 from the effects of the chlorine gas. Chlorine gas destroys the respiratory organs of its victims and leads to a slow death by asphyxiation.

* Chemical warfare agents are chemical substances, whether gaseous, liquid, or solid, which might be employed because of their direct toxic effects on man, animals and plants. Many chemical warfare agents are highly toxic and may persist in the environment for long periods of time. The persistence of these agents depends on humidity, temperature, chemical state, and the type of soil and vegetation in the area. Depending on the agent, human exposure can occur via skin, inhalation or ingestion of contaminated water or food, or entry through areas such as the eyes, nose, and open cuts. Chemical agents are broken into four major types; nerve, blister-vesicant, blood, and pulmonary agents.

Chemical agents can be spread from munitions deliverable by virtually any type of weapon, including mortars, artillery and aircraft. Chemical agent clouds can cover large areas and drift into fighting holes, buildings and bunkers and cause massive casualties.

* Protection against chemical agents is very important to mission accomplishment. After the first German chlorine gas attacks in 1915, allied troops were supplied with masks of cotton pads that had been soaked in urine. It was found that the ammonia in the urine-soaked pads neutralized the chlorine. These pads were held over the face until the soldiers could escape from the poisonous fumes.

Today the Marine Corps uses the M-40 protective mask. This mask protects the face and airways from airborne contamination by all known chemical or biological agents and radioactive dust. Service members using the M-40 can also be aided by escalating levels of mission oriented protective posture (MOPP) by adding protective helmet covers, vinyl overboots, field protective hoods and glove sets.

* To combat the effects of chemical agents in the field, the M-291 skin decontamination kit is a Marines primary means for immediate decontamination of skin following exposure to chemical agents. Each kit consists of six individual decontamination packets, enough to perform three complete skin decontaminations. The black decontamination powder allows you to decontaminate your skin through physical removal, absorption, and neutralization of toxic agents with no long-term effects. Nerve agents such as tabun or sarin may be neutralized by atropine. The role of atropine as a nerve gas antidote is to block the chemicals that control nerve impulses affected by nerve agents from bonding to receptors on the motor nerve endings, thus preventing them from going into spasm. Atropine is normally delivered by a fast-delivery syringe jab into the thigh muscle to ensure that it enters the blood as quickly as possible.

NERVE AGENTS

Nerve agents include tabun, sarin, and soman which disable enzymes responsible for the transmission of nerve impulses and have incapacitating effects that occur within one to 10 minutes of exposure and death within 15 minutes.

* Tabun is a liquid that evaporates only half as fast as mustard gas. It is a powerful poison and even short exposure to small concentrations of its vapor can result in almost immediate symptoms felt first in the eyes and chest. If a lethal dosage has been taken, either from inhalation of the vapor or by absorption of the liquid through the skin, symptoms include running nose, sweating, involuntary urination and defecation, vomiting, twitching, convulsions, paralysis and unconsciousness.

* Sarin is a colorless and odorless gas. It is 26 times more deadly than cyanide gas and only a pinprick-sized droplet will kill a human. The vapor is slightly heavier than air, so it hovers close to the ground. Under wet and humid weather conditions sarin degrades swiftly, but as the temperature rises, sarin's lethal duration increases, despite the humidity. Symptoms include tightness in chest, wheezing, nausea, vomiting, weakness, defecation, urination, paralysis, convulsions, respiratory failure, and death.

* Soman is a colorless, tasteless liquid that dissolves in water. It may have a fruity odor. Soman released into the environment quickly evaporates, disperses, and breaks down. Soman is more powerful than Tabun, acting faster with lower concentration. It can be inhaled, absorbed through the skin, or swallowed. Symptoms can occur within a few minutes up to an hour and include blurred vision, nausea, vomiting, chest tightness, runny nose, convulsions, and death.

BLISTER-VESICANT AGENTS

* Blister agents include lewisite and mustard gas. Blister agents cause blisters on skin and damage the eyes, mucous membranes, respiratory tract and internal organs. Through chemical processes, mustard agents destroy different substances within cells of living tissue. Initial effects are somewhat delayed for mustard gas, occurring 12 to 24 hours after exposure. Symptoms are variable and acute mortality is low, but death can occur from complications after lung injury.

* Mustard gas is an oily liquid with a garlic-like smell. Even in warm weather it evaporates slowly enough for an area over which it has been scattered to remain dangerous for many hours, even days, yet fast enough for the imperceptible vapor that it gives off also to cause casualties. Both vapor and liquid form will burn any body tissue which it touches.

BLOOD AGENTS

* Blood agents are highly volatile, but rapidly acting agents that cause seizures, respiratory failure, and cardiac arrest through interference with absorption of oxygen into the bloodstream. Some blood agents include cyanogen chloride and hydrogen cyanide

PULMONARY AGENTS

Such agents are liquids dispersed in a gaseous form that damage the respiratory tract and cause severe pulmonary edema, fluid in the lungs, in about four hours, leading to eventual death. Effects can be rapid or delayed depending on the specific agent. Pulmonary agents include chlorine, chloropicrin, and diphosgene.

Sempers,

Roger