Analytical Report Of Serial Poisoning Of Iranian Students (Part 3: Unknown chemicals exposure: Signs and Symptoms, Coping Strategies & Seeking Medical Assistance)

In the third section of this series, we will outline potential strategies for managing exposure to unknown chemicals. This will include recognising signs and symptoms of contamination, ways to cope with unknown substances, and obtaining medical help.

It is essential to note that IIPHA aims to investigate the potential factors contributing to the poisoning incidents among students, using the evidence and reports provided by both Iranian students and medical personnel. As we do not have direct access to patients or laboratory samples, this series is based solely on scientific literature regarding known toxic gases and poisoning agents.

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Strategies for Dealing with Chemical Substances

Chemicals can enter the body through three routes: inhalation, ingestion, or skin contact. These substances can be accidentally released into the environment due to human or mechanical errors or intentionally, as in criminal or terrorist acts.

Reports of serial poisoning incidents among Iranian students have only mentioned inhalation as a potential route of exposure. There have been no reports of cases involving skin contact or ingestion.

A strong chemical odour or a visible vapour cloud could mean that a chemical is in the air. However, a bad odour or a visible vapour cloud does not always mean the chemical is harmful, and some toxic chemicals do not have any odour or a vapour cloud.

When encountering an unknown chemical agent, it is best to assume the possibility of contamination and take preventative actions to avoid potential harm.

Symptoms of Chemical Exposure

Mild exposure to chemicals can initially cause symptoms such as tearing and irritation of the eyes, nose, throat, and respiratory tract, which can lead to headaches, dizziness, sweating, blurred vision, stomach pain, nausea, vomiting, and diarrhea. These mild symptoms usually disappear promptly after contact with the chemical is discontinued.

It is important to note that even mild symptoms resulting from exposure to chemical substances can cause anxiety reactions in individuals.

Severe exposure to chemicals can result in more serious complications, such as shortness of breath, coughing, chest tightness, and feelings of fatigue or weakness. In cases of severe exposure to hazardous chemicals, sudden anaesthesia, seizures, and even death can occur.

It should also be noted that symptoms may occur immediately after exposure to chemicals or after a delay of several hours.

Strategies for Dealing with Chemical Exposures

  • Remain calm.
  • Managers and officials should immediately contact emergency services.
  • If in an enclosed space, evacuate immediately and move to an open area.
  • If in an open space, attempt to stay as far away from the potential contamination source as possible.
  • In cases of inhalation exposure to gases and vapours, moving to an open space or avoiding the contaminated environment is generally sufficient. No further decontamination measures are required.
  • Contaminated clothes and accessories should be removed quickly for contact exposure to fluids, and affected skin areas should be washed thoroughly with soap and water. If possible, the entire body, head, and face should be washed with sufficient water and soap.
  • If the eyes are exposed to large amounts of chemical gases or liquids, flushing them with plenty of water is essential.

Strategies for Contamination Control

Individuals exposed to chemical gases who quickly leave the contamination site are unlikely to have their clothes or skin contaminated with chemicals and are unlikely to transmit toxic substances to others. Only in extremely severe gas exposures is there a possibility of contamination remaining on the skin or clothes.

Chemical poisoning can only spread from one person to another if clothing or skin is in direct contact with large amounts of gas or soaked in a chemical liquid. In such cases, removing contaminated clothing reduces the likelihood of contamination transmission by 80-90%.

It should be noted that after removing clothes and personal items such as watches, jewelleries, headbands, wallets, keys, etc., they should be placed out of reach of others to minimize the possibility of contamination spread. The best approach is to place them in a sealed plastic bag.

In severe exposures, contact lenses should be removed quickly, while glasses can be used after being washed thoroughly with plenty of water.

Diagnostic-therapeutic approaches

Trained medical professionals will carry out diagnostic and therapeutic measures in cases of chemical exposure. In some cases of poisoning, physicians can diagnose the possible type of contamination through clinical examinations. If necessary, additional tests, such as blood or urine tests, may be performed based on the physician’s recommendation.

Antidotes can also be used to diagnose and treat acute cases of poisoning. In most mild exposures, the only necessary action is to move away from the source of contamination and, if necessary, remove any contaminated clothing or personal belongings. However, if the affected individuals reveal more severe symptoms, such as acute respiratory problems, seizures, or coma, they must receive long-term care and be hospitalised.


Nerve agents (e.g., Tabun gas, Arsine…)

Nerve agents, such as Tabun gas and Arsine, can cause severe poisoning by inhibiting the acetylcholinesterase enzyme, similar to organophosphates from the pesticide family. These gases can be absorbed quickly through the respiratory tract within seconds to minutes of exposure and may cause symptoms such as a runny nose and shortness of breath.

Recently, there have been reports of poisonings among Iranian students, where the most commonly reported symptoms were related to the gastrointestinal and respiratory systems. These symptoms included dizziness, nausea, vomiting, sore throat, stomach pain, palpitations, chest pain, shortness of breath, nasal discharge, cough, weakness, numbness, and tingling of limbs. Additionally, some students reported smelling scents such as tangerine or mint before the onset of symptoms, while others experienced symptoms suddenly without smelling any odour.

While it’s impossible to determine the type of contamination without laboratory samples, considering the mentioned symptoms, nerve agents and other organophosphates are possible causes of the school poisonings. Trained medical professionals can diagnose the type of poisoning through clinical examination or additional tests, and in severe cases, affected individuals may require long-term care and hospitalisation.

Nerve agents, in their gaseous state, are not typically absorbed through the skin except in liquid form or very high concentrations. Based on reports from Iranian schools and medical personnel, the possibility of skin and digestive exposure to these gases is almost non-existent.

Nerve agents are denser than air, so their concentration is lower in elevated regions. They are often colourless and odourless or have a fruity smell that is not easily detectable by human senses, making it difficult to identify them quickly and prevent exposure.

Nerve agents have been used in wars, such as the Iran-Iraq war, where they were used by the Iraqi army and in terrorist operations, like the 1995 attack on the Tokyo metro in Japan.

Symptoms of exposure to nerve agents often start with constriction of the pupils (miosis), which is usually the first physical sign of low doses of these gases. Other symptoms include blurred vision, headache, increased salivation, excessive sweating, runny nose, tearing, nausea, vomiting, diarrhea, abdominal pain, shortness of breath, and dizziness.

In severe exposures, individuals may experience seizures, muscle cramps, muscle paralysis, and unconsciousness. Some symptoms, such as fatigue, irritability, and memory impairment, may persist for up to six months after exposure. In severe cases, nerve agent exposure can lead to the patient’s death.

If you suspect exposure to nerve agents, follow these steps: It can be challenging to determine the type of contamination without proper testing. Still, if you suspect exposure to nerve agents, following the recommendations outlined in the first part of this article is essential. Remain calm and exit the contaminated area to an area with fresh air. Do not attempt to treat yourself with antidotes or medications, as they can be dangerous if not administered properly. Call emergency services or go to the nearest hospital as soon as possible. Provide as much information as possible about your exposure, including the suspected agent and any symptoms you are experiencing.

It is not necessary to wash your entire body after exposure to nerve agents, but it is recommended to wash the areas of the body that were exposed to contamination. If you experience a burning sensation in your eyes, it is essential to flush them with water.

Once you have left the contaminated area and reached a safe location, it is recommended to wash your head, hair, and body thoroughly. Seek medical attention from paramedics, nurses, or physicians, who will provide specialised treatment and care. Remember, early medical intervention is critical in cases of nerve agent exposure.

Arsine Gas

Arsine gas is a highly flammable colourless gas, also known as hydrogen arsenide or arsenic hydride, with the chemical formula AsH3. It has a distinct garlic or rotten fish-like odour, but the human sense of smell is not always effective in quickly detecting and preventing exposure.

The main route of exposure to arsine is through inhalation, as it is easily absorbed through the respiratory tract, although its skin absorption is minimal. Due to its weight, its concentration is lower in elevated regions.

Arsine gas was previously used by the German army as a chemical weapon during World War I and is still utilised in various industries such as electronics and mining.

Inhaling arsine gas is rapidly absorbed through the lungs and enters the bloodstream and red blood cells, leading to haemolysis. As red blood cells transport oxygen to cells and tissues, the body becomes deficient in oxygen (hypoxia).

Symptoms of exposure may include weakness, headache, dizziness, restlessness, thirst, tremors, fever, increased heart rate, nausea, vomiting, abdominal pain, and shortness of breath. In severe exposures, poisoning symptoms can occur within 30 to 60 minutes after exposure, although they may also manifest 2 to 24 hours later.

Haemolysis caused by arsine gas exposure can result in haemoglobinuria, which is characterised by urine discolouration (red, orange, or brown), jaundice, kidney failure, and other serious health issues.

If you suspect exposure to arsine gas, it can be challenging to provide an accurate and scientific response without knowing the specific type of contamination. As a general guideline, you should remain calm, move away from the affected area, seek fresh air, call emergency services, and wash the affected skin thoroughly. Since arsine gas is not absorbed through the skin, there is no need to decontaminate or remove clothing or wash your face or hands.

If there is a possibility of exposure to multiple substances, it is recommended to take precautionary measures and consider all possible agents. This includes following the recommendations given in the introductory section of the article, such as leaving the environment and entering an open space with fresh air, contacting emergency services, and washing the parts of the skin that were exposed to contamination. Decontamination measures should also be taken as necessary. It is important to note that medical and specialised treatments should be carried out by trained professionals such as emergency personnel, paramedics, nurses, and physicians.

The information on this topic is subject to change as new evidence emerges, and the report will be updated accordingly.