What is Chloroethane?

Chloroethane, or monochloroethane, commonly known by its old name ethyl chloride, is a chemical compound with the chemical formula C₂H₅Cl. It is a colourless flammable gas at ordinary temperature and pressure. It has a characteristic ether-like odour and a burning taste. Chloroethane burns with a smoky, greenish flame, which is a result of the production of hydrogen chloride. It reacts violently with oxidants, alkaline metals, calcium, magnesium, aluminium powder, and zinc. It reacts with water or steam, producing corrosive fumes of hydrogen chloride.

What is Chloroethane used for?

Chloroethane has several uses across various fields:

• Chemical Intermediate: Used to manufacture foamed plastics.
• Solvent: Suitable for dissolving phosphorus, sulfur, fats, oils, resins, and waxes; also used in insecticides.
• Aerosols and Anaesthesia: Formerly used in medical anaesthesia.
• Blowing Agent: Currently used to create foamed plastics.
• Fuel Additives: previously used to produce tetraethyl lead, an anti-knock additive for leaded gasoline.
• Ethylating Agent: Employed in the manufacture of dyes, drugs, chemicals, and pharmaceuticals.
• Refrigerant: Provides cooling in certain applications.
• Medical Applications: Used as a topical anaesthetic for numbing skin, such as for ear piercings, biopsies, and sports injuries.
• Dentistry: Functions as a pulp vitality tester.
• Pain Relief: Relieves pain from insect bites, stings, tinea lesions, and other skin irritations.
• Counterirritant: Helps manage myofascial and visceral pain syndromes.

These diverse uses make chloroethane valuable across industries including manufacturing, medicine, and dentistry.

Chloroethane in the Environment

Most chloroethane exists as a gas in the atmosphere. It breaks down fairly rapidly (about half disappears within 40 days) by reacting with other substances in the air. Small amounts can enter groundwater by filtering through the soil. In groundwater, chloroethane is slowly changed into a simpler form by reaction with water. Some types of bacteria in water may break it down to smaller compounds.

Sources and Routes of Exposure

Sources of Emission

• Industry: Released from factories that produce or use it, as well as from some landfills, solvents, refrigerants, and anesthetics. Emissions can also occur from burning plastics and shipping accidents.
• Diffuse Sources: Trace amounts may enter drinking water from chlorination, contamination, or seepage into groundwater from waste sites.
• Natural Sources: Formed through microbial breakdown of other chlorinated solvents in soil.
• Consumer Products: Found in foamed plastics, some pharmaceuticals, cosmetics, solvents, refrigerants, sports sprays, and anaesthetics used for ear and body piercing.

Routes of Exposure

Main exposure routes include:

• Inhalation
• Skin absorption (liquid form)
• Ingestion (liquid form)
• Skin and/or eye contact

Health Effects

Acute Effects

High levels of chloroethane inhalation can cause temporary feelings of drunkenness, dizziness, loss of muscle coordination, and even unconsciousness. Its former use as an anaesthetic during surgery led to accidental deaths. Animal studies (rats and mice) show low toxicity from short-term inhalation exposure.

Chronic Effects

Prolonged exposure to high concentrations may lead to neurological symptoms like ataxia, tremors, speech issues, slowed reflexes, involuntary eye movements, and hallucinations. Liver effects were also reported. Animal studies indicate potential effects on lungs, liver, kidneys, and heart. The EPA set the Reference Concentration (RfC) at 10 mg/m³ for chloroethane, but there is no established Reference Dose (RfD).

Reporductive/Developmental Effects

No human studies on reproductive or developmental impacts exist. Animal studies showed no reproductive effects, though some studies found decreased uterine weights and slight fetotoxicity (unossified skull bones).

Cancer Risk

Human data on cancer risks are unavailable. A 2-year animal study found that inhaled chloroethane led to uterine and liver tumours in female mice and some tumours in rats. The EPA has not classified chloroethane for carcinogenicity.

Chloroethane Safety

First Aid Measures

• Eye Contact: Remove contact lenses if present. Rinse eyes with water for at least 15 minutes. Avoid using eye ointments. Seek medical attention.
• Skin Contact: Wash skin thoroughly with water and mild soap. Clean all folds and creases carefully. Use an emollient on irritated skin. Seek medical attention if irritation persists. Wash contaminated clothing before reuse.
• Inhalation: Move the person to fresh air and seek immediate medical attention.
• Serious Inhalation: The rescuer should wear a mask or self-contained breathing apparatus. Move the person to a safe area. If breathing is difficult, give oxygen; if not breathing, perform CPR carefully. Seek immediate medical help.
• Ingestion: Chloroethane is mainly inhaled rather than ingested. Prioritise inhalation first aid measures.

Fire & Explosion Information

Flammability: Chloroethane is flammable with open flames or sparks.

• Auto-Ignition Temp: 519°C (966.2°F)
• Flash Points: Closed Cup: -50°C (-58°F); Open Cup: -43°C (-45.4°F)
• Flammable Limits: 3.6% (Lower), 15.4% (Upper)

Extinguishing Fires: Use dry chemical powder for small fires. For large fires, use water spray, fog, or foam (avoid water jets).

Fire Handling: If possible, move containers from the fire area. Cool containers with water to prevent pressure buildup. Do not extinguish a leaking gas flame unless the leak can be stopped. Handle damaged cylinders with extreme care.

Exposure Controls & Personal Protection

Engineering Controls

• Ventilation is normally required when handling or using this product.

Personal Protective Equipment

The following personal protective equipment is recommended when handling chloroethane:

• Splash goggles;
• Lab coat;
• Vapour respirator (be sure to use an approved/certified respirator or equivalent);
• Gloves

Personal Protection in Case of a Large Spill:

• Splash goggles;
• Full suit;
• Vapour respirator;
• Boots;
• Gloves;
• A self-contained breathing apparatus should be used to avoid inhalation of the product. 
• Suggested protective clothing might not be sufficient; consult a specialist BEFORE handling this product.

Regulation

United States

• EPA: The Environmental Protection Agency requires industries to report accidental discharges or spills of 100 pounds or more of chloroethane to EPA.
• OSHA: The Occupational Safety and Health Administration regulates the amount of chloroethane in workplace air. The limit for an 8-hour workday over a 40-hour workweek is 1,000 parts per million (1,000 ppm).
• ACGIH: The American Conference of Governmental Industrial Hygienists (ACGIH) recommends a limit of 100 ppm chloroethane in workplace air.

Australia

• Safe Work Australia: Safe Work Australia has established a maximum time-weighted average (TWA) exposure concentration for chloroethane of 1,000 ppm and 2,640 mg/m3