Chemical agents used as weapons are capable of producing significant morbidity and mortality, causing panic and disorder in society. The chemicals with the potential to be used as arms in chemical warfare, clear and rapid effects.
Characteristics of chemicals:
– Volatility: is the tendency of the chemical into a vapor. Among the more volatile are phosgene and cyanide. The victim must stand to avoid heavy exposure the chemical down to the floor or ground.
– Persistence: means that the substance is less likely to vaporize and disperse. Chemical agents used as weapons, such as those that are developed by the military are more likely to penetrate and cause secondary exposure.
– Toxicity is the potential for an agent to cause injury to the body.
– Latency is the time between absorption and onset of symptoms.
Vesicant chemicals:
These substances are capable of causing blisters and burns result in conjunctivitis, bronchitis, pneumonia, haematopoietic suppression, and death. Some of the substances are vesicant lewisite, phosgene, nitrogen.
After exposure to the vesicant, the first signs are similar to a large surface burn partial thickness in the warm, moist areas of the body (perineum, axillae and anticubital spaces). There are itching and redness for about 24 hours, followed by itching, burning, blistering and painful little after 2 to 18 hours.
These vesicles may coalesce to form a fluid-filled blister. Lewisite and phosgene results in pain immediately after exposure, the tissue injuries manifest themselves in a few minutes. If eyes are exposed, there is pain, photophobia, tearing and decreased vision, conjunctivitis symptoms progress, blepharospasm, corneal ulcers and edema.
Respiratory effects are more severe and are often the cause of death from exposure to a vesicant. Purulent discharge from the fibrinous pseudomembrane leads to obstruction of the airways. Gastrointestinal exposure include nausea and vomiting, leukopenia, and bleeding from the upper gastrointestinal tract.
Nerve Agents:
They are the most toxic agents, among which are malathion, sarin, soman, tabun, VX and organophosphate (Pesticides). In liquid form, evaporate to form a colorless, odorless vapor. Nerve agents can be inhaled or absorbed percutaneously or subcutaneously, together with the acetylcholinesterase so that acetylcholine can not be removed, the side effect is continuous stimulation (hyperstimulation) of the nerve endings.
A very small drop of the agent sufficient to cause sweating and spasms at the site of exposure, and results in much more general symptoms. The effects may begin 30 minutes to 18 hours after exposure.
Signs and symptoms of exposure to nerve gas are the same cholinergic crisis include bilateral miosis, impaired vision, gatrointestinal increased motility, nausea and vomiting, diarrhea, spasm, substernal, indigestion, bradycardia and atrioventricular block, bronchoconstriction, laryngeal spasm, weakness, twitching, and incontinence.
Neurological reactions include insomnia, impaired memory, impaired judgment, depression and irritability. A lethal dose resulting in loss of consciousness, convulsions, copious secretions, fasciculations, flaccid muscles, and apnea.
Blood Agents:
Blood agents like hydrogen cyanide and cyanogen chloride, directly affect cell metabolism, resulting in suffocation by changes in hemoglobin. Cyanide is an agent that has profound systemic effects. The release of cyanide is often associated with the smell of bitter almonds.
In the home fires cyanide is released by burning plastics, carpets, silk, furniture and other building materials. There is a significant correlation between blood levels of cyanide and carbon monoxide in fire victims and the most frequent cause of death is cyanide, which can be ingested, inhaled or absorbed through the skin and mucous membranes .
The cyanide protein binds to and inhibits the aerobic metabolism, resulting in failure of respiratory muscles, respiratory arrest, cardiac arrest and death. Inhalation of cyanide results in redness, tachypnea, tachycardia, nonspecific neurological symptoms, stupor, coma and convulsions prior to respiratory arrest.
Pulmonary Agents:
Pulmonary agents such as phosgene and chlorine destroys the membrane separating the alveoli pulmonary capillary bed, so that the exposed person can not release carbon dioxide and oxygen gain. Capillary leakage resulting in fluid-filled sacs. Both phosgene and chlorine quickly vaporize and cause lung injury. The phosgene has the aroma of freshly cut hay.
Signs and symptoms include pulmonary edema with shortness of breath especially on exertion. The cough begins as a dry cough followed by the production of frothy sputum. The only protection that is required is a mask. Phosgene not injure the eyes.
To calculate the impact of the chemical agent used as a weapon is considered as the median lethal dose amount of the substance resulting in death in 50% of exposed individuals, while the average effective dose is the cause signs and symptoms in 50 % of them. The time of concentration is the concentration released multiplied by the exposure time.
