Tear Gas

1. What is Tear Gas?

The term "tear gas" is a misnomer; it is not a gas but a solid or liquid particulate that disperses as a fine aerosol or dust. The primary function of these compounds is to act as lacrimators, chemicals that irritate the eyes and mucous membranes, causing tearing, pain, and temporary incapacitation.

Chemical Varieties

Two primary compounds are used:

• CS (2-chlorobenzalmalononitrile): This is the most common form, used widely by law enforcement and the military. It is a crystalline solid that is a powerful lacrimator and irritant. Its effects are typically temporary.

• CN (Chloroacetophenone): An older compound, less potent than CS. While still an irritant, it is less common today due to its higher toxicity.

In addition to these, pepper spray contains capsaicin, a potent irritant derived from chili peppers. While its effects are also temporary, it is important to note that all of these compounds are designed to cause pain and irritation on contact.

2. Health Effects of Exposure

The health effects of tear gas exposure are twofold: the immediate, acute effects of a direct exposure event and the chronic, lingering effects of residue contamination.

Acute Effects

Upon initial exposure, tear gas causes:

• Ocular: Intense, involuntary tearing, burning, redness, and pain in the eyes.

• Respiratory: Burning in the nose and throat, coughing, shortness of breath, and chest tightness.

• Dermal: A stinging or burning sensation on the skin.

These acute symptoms typically resolve within 15-30 minutes of leaving the contaminated area and getting to fresh air.

Chronic Effects of Lingering Residue

This is where the role of an industrial hygienist becomes crucial. If a property is not properly decontaminated, the fine particulate residue remains, posing a continuous exposure risk. This residue is microscopic, odorless, and can be easily re-aerosolized into the air by walking on a contaminated carpet, opening a door, or turning on an HVAC system.

• Chronic Respiratory Issues: Long-term, low-level exposure to residue can lead to persistent coughing, bronchitis, asthma, and chronic irritation of the airways.

• Dermal (Skin) Problems: The residue can cause contact dermatitis, rashes, and a persistent itching or burning sensation on the skin.

• Ocular Irritation: Chronic eye irritation, redness, and inflammation can occur in occupants who are constantly exposed to the residue.

The real danger is that occupants may be unaware of the cause of their symptoms, attributing them to allergies or other environmental factors, while the tear gas residue continues to harm their health.

3. Ineffective Cleaning and Associated Risks

Standard cleaning methods are completely ineffective against tear gas residue and will only exacerbate the problem. Using a dry vacuum, for example, will simply re-aerosolize the fine particles and spread them to other rooms.

The Dangers of Ineffective Cleanup:

1. Chemical Spreading: The tear gas compound will penetrate and absorb into porous materials. Simply wiping down a surface may not remove the residue. When a contaminated surface is wiped with a wet cloth, the compound can dissolve and be spread to other, previously clean surfaces.

2. Cross-Contamination: Without proper containment and negative air pressure, the decontamination process itself can spread the chemical from one area to another via the HVAC system or airflow patterns.

The Correct Remediation Protocol

Proper remediation is an extensive, multi-step process that often requires professional assistance. It is similar to a hazmat cleanup.

1. Containment: The affected area must be sealed off to prevent cross-contamination.

2. Negative Air: Air filtration devices with HEPA and specialized carbon filters must be used to capture the airborne particles and chemical vapors.

3. Removal of Porous Materials: All porous materials (carpets, curtains, bedding, etc.) must be removed and disposed of as hazardous waste, as they cannot be effectively decontaminated.

4. Specialized Cleaning: All non-porous surfaces must be meticulously cleaned with a specialized decontaminant solution that breaks down the chemical. This involves multiple stages of cleaning, rinsing, and wiping.

5. HVAC Decontamination: The entire HVAC system and ductwork must be professionally cleaned and decontaminated, as they can act as reservoirs for the chemical.

In summary, tear gas is a potent chemical that leaves a persistent, invisible, and highly hazardous residue. The only safe way to address contamination is through a complete and professional remediation process that includes containment, specialized cleaning agents, and proper disposal. Anything less poses a significant and ongoing health risk.