Egypt is 1 of 5 nations that haven’t signed the Chemical Weapons Convention & are unhindered by restrictions on use of CS gas.
- If you have any information / references about these substances please use the comment section and I will add it to the page. Thank you.
NATO codes of Riot Control Agents (RCAs)
- CS: o-chlorobenzylidene malononitrile
- OC: oleoresin capsicum (OC )
- PS: chloropicrin
- CN: 1-chloroacetophenone
- DM: diphenylaminearsine
- CR: dibenz(b,f)(1,4)oxazepine
Reports from Tahrir Square
Some reports it was CS gas other reports indicate CR gas. I personally witness many victims with their faces covered in white powdery material which seems in line with CS gas (see below). I cannot confirm it was due to tear gas exposure.
Some have indicated tingling sensation, nervous system reactions including seizure like reactions that seems to be relieved by low-dose (3-5mg) diluted diazepam given slowly IV. In the table below OC (pepper spray) does exhibit sensory nervous manifestations. It is important to note that OC is commercially available in concentrations of 1% but is available at much higher concentrations up to 10% as a riot control agent. There are some unconfirmed reports that pepper spray was associated with lethal seizures. Also note that pepper spray responds to decontamination with vegetable oil (see table).
What is probably happening is several types of gas are being used, which makes it confusing.
In terms of treatment some from Tahrir have advised the following:
- Mucogel / epicogel seems harmless enough, is alkaline but I cannot tell what the effects are of rubbing it on the eyes? Especially these antacids contain magnesium and aluminium therefore any acid-base reaction can leave a magnesium or aluminium precipitate which can be harmful to the eye.
- Zantac (ranitidine) is an antacid that works through blocking the H2 receptors. Unlike the antacids mentioned above a solution of Zantac is not alkaline and therefore ineffective when used to neutralize an acid.
- Some have advised water should never be used with certain tear gas. It should always be used when indicated in the table below. You should note that water will increase the symptoms but is essential for decontamination.
- Onions. Reports that onions are effective but I cannot back that with any evidence. The only documentation seems to come from Palestinian activists. One expert attributes its effect to sulfur content, but no confirmation in medical or scientific literature.
- Hydrazine is more concerning since it is toxic. Should never be used.
UPDATE: Human rights officials tell BBC that “military grade” CS gas is being used in Tahrir, not the routine crowd control stuff via @WyreDavies. Interesting side note: Use of CS in war is prohibited under the terms of the 1997 Chemical Weapons Convention, signed by all but five nations. These five nations are therefore unhindered by restrictions on the use of CS gas: Angola, Egypt, North Korea, Somalia, and Syria.
All RCAs cause some form of eye irritation involving lacrimation and blepharospasm, which causes the eyes to close temporarily, rendering victims unable to see and dramatically reducing their ability to resist. PS, CN , CS, CR , DM, and OC also cause irritation to airways resulting in coughing, shortness of breath, and retching or vomiting. DM in effective doses causes significant vomiting with resulting mental depression and malaise. These agents cause some degree of pain sensation.
The reflex most associated with death from the inhalation exposure of the irritants is the Kratschmer reflex, as the immediate response of cessation of respiration. The response is a protective reflex or defense mechanism to prevent or reduce the amount of noxious chemical reaching the lower respiratory tract and maintain homeostasis. During cessation of respiration, blood levels of carbon dioxide increase and drive the respiratory center to restart breathing. Individuals with compromised immune systems, nervous system depression as a result of alcohol or illicit drug consumption, or a combination of these, may not be able to restart respiration and die from asphyxia.
Table comparing different types
Use this table to help determine the most likely agent that you have been exposed to.
|OC (Pepper Spray)|
|Physical State||Colorless oily liquid||Colorless to gray, crystalline solid||Light yellow to canary, green crystals||Pale yellow crystalline solid||White crystalline solid.||Colorless solid.|
|Odor||Strong, sharp, pungent and highly irritating odor||Fragrant (like apple blossoms)||Odorless or not pronounced. May be mildly irritating.||Pepper-like||Pungent pepper like||Pungent irritating|
|Skin and eyes||Irritation, itching, rash, and blisters on exposed skin. Eye lacrimation pain, and burning appear below the threshold of the odor.Very potent lacrimator.||Primarily skin redness. Can develop blisters and burns on moist tissuedue to HCL formation. Strong lacrimator with redness of eyes, eye pain, and blepharospasm. High dose may produce chemical injury to eye.||Significant nasal discharge. The amount needed to cause skin irritation and redness is above that needed for irritation of respiratory and gastrointestinal tract. Only slight eye irritation is reported when throat and chest irritation is present.||Burning of skin, particularly in a hot moist environment. Redness and blistering are possible with lengthy exposure. Producesviolent lacrmination of the eyes with a burning, redness and lid redness.||Skin irritant; itching, stinging and erythema; may cause blistering and allergic contact dermatitis. Burning and irritation to eyes with lacrimation and accompanying blepharospasm||Causes sensation of intense pain and burning through the activation of the TRPV1 sensory neuron, causing release of substance P. May cause allergic dermatitis with excessive skin exposure. Lacrimation, redness, burning sensation in the eyes and blepharospasm.|
|Respiratory effects||Immediate burning sensation in nasal passages, choking, and inhibition of respiration. Can cause lung lesions.||Upper respiratory irritation, cough, dyspnea. Can also produce tissue burns of the airway and pulmonary lesions if dose is significant.||Sneezing, coughing, salivation and congestion of the nose and upper airway to produce a feeling of suffocation.||Burning sensation and pain in throat with subsequent feeling of suffocation.||Salivation, coughing, choking, and a feeling of chest tightness. May cause reactive airway disease syndrome requiring medical intervention.||Tingling sensation followed by coughing and decreased inhalation rates. Pain, vasodilation, and secretion can occur in the airways depending on the dose inhaled|
|Other effects||Produces initial nausea followed by violent retching and vomiting, which can occur 20-30 minutes after initial exposure. Can also produce perspiration, chills, mental depression abdominal cramps and diarrhea lasting several hours.||Anxiety and fatigue.|
|Clothing||Move to fresh air; remove clothing, do not wear again until properly laundered or discard||Move to fresh air; remove clothing and wash before wearing again||Move to fresh air, remove clothing and wash before wearing again||Move to fresh air; remove clothing and wash before wearing again||Stand in front of a fan or flap arms to remove dry powder, protect airway. Wash clothing after removal.||Sticks to clothing if in liquid solution. If in powder form, remove dry powder. Wash clothing after removal.|
|Skin||Copious soap and water||Copious soap and water||Copious soap and water||Copious soap and water or use 5% or 10% sodium bicarbonate which is more effective than water||Copious soap and water; do not use oil-based lotions or bleach.||Copious soap and water. Can also use alcohol, baby shampoo, or flush skin with vegetable oil followed by soap and water (not for OC/CS-CN mixtures);flush eyes with copious water or baby shampoo; usemilk or ice packs to reduce pain|
The effects from RCAs are typically self-limiting, and discomfort is reduced within 30 minutes upon exiting a contaminated area. Usually no medical treatment is necessary, particularly if the agent is used in an open area and the dose is minimized.
Injury may range from skin and eye irritation to, in rare cases, injuries sustained from exploding dispensing munitions, delayed transient pulmonary syndromes, or delayed pulmonary edema requiring hospital admission.
Short-term protection can be provided by dry clothing that covers the arms and legs, because sweat allows dry agents to adhere to the skin. The standard protective mask will adequately protect against the inhalation of RCA particles and vapors. CS1, CS2, or CR, exposure in large quantities requires protective clothing, mask, and gloves that cover all exposed skin areas should be worn.
Decontamination is important to reduce injury and continued exposure from agent on the skin, hair, and clothing. This is particularly important for those in contact with RCAs in enclosed areas for long periods of time, such as individuals running mask confidence training who are in the chamber repeatedly throughout a single day. Large amount of exposure to CS has resulted in erythema (red skin), minor skin burns, and blistering on the neck, arms, and other areas that were not continuously protected by a mask or clothing.
If unable to wear adequate dermal protection during exposure one MUST shower immediately with soap and water as soon as they return home.
When dry agents (CS, CR, CN, and DM) are dispensed in the open air in limited quantities, all that is needed to remove the agent, particularly when protective clothing is worn, is brisk movement: flapping the arms and rubbing the hair in a breeze or standing in front of a large fan. This will disperse most of the particles from the clothing and hair.
The mask should be worn during this process to insure that particles blown from other people performing the same procedure upwind are not inhaled. However, agent particles adhere to sweaty skin, so completely effective decontamination requires clothing removal followed by thorough washing of exposed skin and hair. Contaminated clothing should be removed and if laundered, cold water should be used to reduce vaporization of the agent.
Soap and water are an effective decontaminant for RCAs; they will not neutralize the agent but will wash it away. Water should be used in copious amounts. Soap helps loosen the dry particles and remove them adequately from the skin surface.
CR, CN and DM hydrolyze very slowly in water, even when alkali is present. Because these agents do not decompose in water, washing with soap and water will only remove them from surfaces. Run-off may produce irritation if it gets into the eyes, so the eyes should be closed and head lowered during decontamination (if the agent is not already in the eyes). Environmental contamination from these agents may be persistent and difficult to remove. CS is insoluble in water but will hydrolyze in water at a pH of 7, with a half-life of approximately 15 minutes at room temperature, and extremely rapidly in alkaline solution with a pH of 9, with a half-life of about 1 minute.
Decontamination solutions used on human skin should not be caustic to the skin. A solution containing 6% sodium bicarbonate, 3% sodium carbonate, and 1% benzalkonium chloride was found to bring prompt relief of symptoms and to hydrolyze CS. No form of hypochlorite should ever be used to decontaminate CS or other RCAs because it can react with CS to produce more toxic chemical byproducts and will further irritate tissues. Applying water or soap and water to skin exposed to CS or OC but decontaminated may result in a transient worsening of the burning sensation, which should dissipate with continued water flushing. PS liquid can also be decontaminated with soap and water, and clothing, which can trap vapor, should be removed.
Water in limited quantities increases the pain symptoms from OC, which has a water solubility of 0.090 g/L at 37° C. Without decontamination, OC symptoms should dissipate over time as the body’s substance P is diminished. OC resin can also be decontaminated with copious amounts of water, liquid soap and water, baby shampoo, alcohol, or cold milk. OC in the eyes can be decontaminated with copious water flushing, but symptoms may not dissipate for 10 minutes.
A compress of cold milk, ice water, or snow can help reduce the burning sensation once the individual has been decontaminated. Substances with high fat content, such as whipped cream or ice cream, also aid in decontamination and help reduce pain. Although OC is soluble in vegetable oil and other hydrocarbons, and such solutions can more easily be washed off the skin, hydrocarbons must not be used with solutions of OC and other RCAs such as CN.
The following is a list of commercially available products in the United States (I will update the list for Egypt – please use a Google search).
- Sudecon Decontamination Wipes (Fox Labs International, Clinton Township, Mich);
- Bio Shield towelettes (Bio Shield, Inc, Raleigh, NC) or Cool It!
- Wipes and spray (Defense Technology, Casper, Wyo); claim to help decontaminate and reduce pain in people exposed to pepper sprays and other RCAs.
Skin erythema (red coloration) that appears early (up to 1 hour after exposure) is transient and usually does not require treatment. Delayed-onset erythema (irritant dermatitis) can be treated with a bland lotion such as calamine lotion or topical corticosteroid preparations (eg, 0.10% triamcinolone acetonide, 0.025% fluocinolone acetonide, 0.05% flurandrenolone, or betamethasone-17-valerate). Cosmetics, including foundation and false eyelashes, can trap agent and should be removed to insure complete decontamination.
When the patient has been exposed to OC, the use of creams or ointments should be delayed for 6 hours after exposure.194 Patients with blisters should be managed as having a second-degree burn. Acute contact dermatitis that is oozing should be treated with wet dressings (moistened with fluids such as 1:40 Burow solution or colloidal solution) for 30 minutes, three times daily. Topical steroids should be applied immediately following the wet dressing.
Appropriate antibiotics should be given for secondary infection, and oral antihistamines for itching. Vesicating lesions have been successfully treated with compresses of a cold silver nitrate solution (1:1,000) for 1 hour, applied six times daily. One person with severe lesions and marked discomfort was given a short course of an oral steroid. An antibiotic ointment was applied locally, but systemic antibiotics were not used. With severe blistering resulting in second-degree burns, skin pigmentation changes can occur.
The effects of RCA s on the eyes are self-limiting and do not normally require treatment; however, if large particles of solid agent are in the eye, the patient should be treated as if for exposure to corrosive materials. The individual should be kept from rubbing the eyes, which can rub particles or agent into the eye and cause damage. Contact lenses should be removed.
With all agents, the affected eyes should be thoroughly flushed with copious amounts of normal saline or water for several minutes (some sources suggest 10 minutes) to remove the agent.
At the hospital:
Eye injury assessment should include a slit lamp examination with fluorescein staining to evaluate for corneal abrasions that could be caused by rubbing particles of the agent into the eye. Patients should be closely observed for development of corneal opacity and iritis, particularly those who have been exposed to CN or CA. A local anesthetic can be used for severe pain, but continued anesthetic use should be restricted. If the lesion is severe, the patient should be sent for definitive ophthalmologic treatment.
CS exposure was reported to have been decontaminated with Diphoterine (Prevor, Valmondois, France), which dramatically resolved the effects in four of them. The researchers also recommended using it as a prophylaxis to reduce or prevent lacrimation, eye irritation, and blepharospasm.
3. Respiratory Tract
Typically, RCA -induced cough, chest discomfort, and mild dyspnea are resolved within 30 minutes after exposure to clean air. Some reports suggest that severe respiratory effects may not become manifest until 12 to 24 hours after exposure. If persistent bronchospasm lasting several hours develops, systemic or inhaled bronchodilators (eg, albuterol 0.5%) can be effective in reducing the condition.
Individuals with prolonged dyspnea or objective signs such as coughing, sneezing, breath holding, and excessive salivation should be hospitalized under careful observation. Treatment in these cases may include the introduction of systemic aminophylline and systemic glucocorticosteroids. A chest radiograph can assist in diagnosis and treatment for patients with significant respiratory complaints.
If respiratory failure occurs, the use of extracorporeal membrane oxygenation can be effective without causing long-term damage to the lungs. High-pressure ventilation, which can cause lung scarring, should not be used. Although people with chronic bronchitis have been exposed to RCA s without effects, any underlying lung disease (eg, asthma, which affects one person in six) might be exacerbated by exposure to CS. In most cases the respiratory system quickly recovers from acute exposure to RCAs, but prolonged exposure can predispose the casualty to secondary infections.
4. Cardiovascular System
Transient hypertension and tachycardia have been noted after exposure to RCA s, primarily because of the anxiety or pain of exposure rather than a pharmacological effect of the compound. Whatever the cause, adverse effects may be seen in individuals with hypertension, cardiovascular disease, or an aneurysm.
SUMMARY OF GUIDELINES
Provided by Dr. Hany Ragy (@Hragy):
1-cloth on nose and mouth.
2-wash skin or clothes if sprayed.
3-oxygen and hospital for respiratory.
Most importantly rinse eyes if exposed and stinging (by spraying water on it – do not wash with hands which are contaminated with tear gas).
Additional points provided by Dr. Hany F. Hanna (@hanyfhg)
4. breathe inside your shirt if no vinegar or lemon soaked towel is available and wash skin (not eyes / mouth) with soap and water
5. clothes are to be washed alone the first time before wearing them again
6. contact lenses to be removed immediately or better avoided, take as much water as u can worth all its weight
7. all jewelry to be removed and washed or not worn again if not able to wash
@mugli added these tips for CR gas:
- Dry of skin immediately because CR gas effects wet areas stronger!
- Do only eat packed food. CR gas is a dust which settles on everything, also on food cooking in open pans etc.
- Have tissues in a properly closed package to avoid contamination.
These are my own notes:
Tear Gas works by causing inflammation to nose and eyes.
However, the gas only rises up to 4 meters in the air.
- If possible rise above the gas up to 5 meters but watch out for wind which could blow the gas in any direction.
- Glasses (swimming goggles) and cloth (كمامة) with vinegar (lemon or orange, onion oil also work).
- You must leave the scene to fresh air.
Do not wash face with water. Because your hands will have be contaminated with the chemicals.
Use cold water and spray on face (not hands).
This article was composed on November 22, 2011 at a time when protesters in Tahrir Square were being attacked by unknown tear gas. I used several sources including the tweeps mentioned above. Some sources were copied outright in haste and underlined for emphasis. I apologize to the respective authors. I include these sources below.
Harry Salem, PhD; Bradford W. Gutting, PhD; Timothy A. Kluchinsky, Jr, phD, MSPH; Charles H. Boardman; Shirley D. Tuorinsky, MSN and Joseph J. Hout. Medical Aspects of Chemical Warfare. Chapter 13 – Riot Control Agents.