Safety, Storage, and Handling Guidelines for Ethylidene Chloride (CAS 75-34-3)

Ethylidene chloride, also known as 1,1-dichloroethane (CAS 75-34-3), is a chlorinated hydrocarbon used primarily as a solvent in cleaning and extraction processes, an intermediate in chemical manufacturing (e.g., for 1,1,1-trichloroethane), and in adhesives or specialty chemicals. Its volatility and reactivity make it valuable in industrial applications, but these properties also pose significant risks, including flammability, toxicity, and environmental persistence. Safety and storage guidelines are critical due to its classification as a hazardous substance, potential for carcinogenicity, and regulations under agencies like OSHA and EPA, which mandate proper handling to prevent exposure and incidents.

Chemical Identity & Properties

Ethylidene chloride is systematically named 1,1-dichloroethane, with synonyms including ethylidene dichloride and asymmetrical dichloroethane. It has the molecular formula C₂H₄Cl₂ and structure CH₃CHCl₂, featuring a geminal dihalide configuration. Key physical and chemical properties include: appearance as a colorless liquid with a chloroform-like odor; boiling point of 57.2°C; flash point of -17°C; density of 1.2 g/cm³ at 20°C; vapor pressure of 182 mmHg at 20°C (indicating high volatility); and low solubility in water (0.6% at 20°C) but miscibility with organic solvents. It is classified as a flammable liquid (Category 2), acute toxicant (Category 4, oral), and irritant under GHS, with potential carcinogenic effects.

Hazard Identification

Health hazards include acute effects from inhalation (dizziness, nausea, CNS depression), ingestion (gastrointestinal irritation), skin contact (irritation, defatting), and eye contact (severe irritation). Chronic exposure may lead to liver, kidney, or cardiovascular damage, with IARC classifying it as a possible human carcinogen (Group 2B). Environmental hazards involve atmospheric persistence (half-life ~62 days) and potential for groundwater contamination due to volatility and mobility. Regulatory status includes OSHA PEL of 100 ppm (TWA), GHS pictograms for flame, exclamation mark, and health hazard (H225: Highly flammable; H302: Harmful if swallowed; H351: Suspected of causing cancer), and inclusion under REACH (Annex XVII restrictions) and EPA TSCA.

Safe Handling Guidelines

Handle in well-ventilated areas or closed systems to minimize vapor exposure, with exhaust systems at the workplace to prevent aerosol formation. PPE requirements include chemical-resistant gloves (e.g., nitrile), goggles or face shields, protective clothing, and respirators (e.g., SCBA for high concentrations). Avoid ignition sources like sparks or flames, and prohibit eating, drinking, or smoking in handling areas. Best practices for transfer include using grounded equipment and dispensing in fume hoods, with workers trained on hazards and washing hands after handling.

Storage Recommendations

Store in a cool, dry, well-ventilated area away from heat, sunlight, and incompatible substances like strong oxidizers (e.g., peroxides), alkali metals, or strong bases, which may cause violent reactions. Use approved containers such as metal drums or glass bottles that are tightly sealed to prevent vapor release. Segregate from food, pharmaceuticals, oxidizers, and reducing agents to avoid contamination or reactions.

Spill & Leak Response

For spills, immediately evacuate the area and ventilate to disperse vapors. Contain the spill using non-combustible absorbents like sand, earth, or vermiculite, avoiding sparking tools. Collect material in labeled containers for disposal as hazardous waste per local regulations, preventing entry into drains or waterways.

First Aid Measures

For inhalation, move the victim to fresh air; if breathing is difficult, administer oxygen and seek medical attention. For skin contact, remove contaminated clothing and wash with soap and water for at least 15 minutes. For eye contact, flush with large amounts of water for 15+ minutes, lifting eyelids, and consult a physician. For ingestion, do not induce vomiting; seek immediate medical help and provide SDS to responders.

Firefighting Measures

Use suitable extinguishing media like alcohol-resistant foam, CO₂, or dry chemical powder; water spray may be ineffective but can cool containers. Fire hazards include release of toxic gases such as HCl, CO, and phosgene. Firefighters should wear full protective gear, including SCBA, and fight fire from a safe distance to avoid vapor explosions.

Disposal Considerations

Ethylidene chloride is classified as hazardous waste (EPA waste code U076). Dispose via licensed hazardous waste contractors through incineration or approved methods, avoiding release to soil, water, or sewers. Contaminated packaging should be treated as hazardous and disposed similarly.

Regulatory & Compliance Notes

It has UN number 2362 (flammable liquid, toxic) and is classified under DOT/IMDG/IATA as Hazard Class 3 (Packing Group II), with labels for flammable liquid and toxic. For exports from China, CIQ危包证 certification is required for hazardous packaging. Comply with OSHA (PEL 100 ppm), EPA (TSCA listed), and REACH requirements for labeling and transport.

Compliance with safety, storage, and handling guidelines is essential to mitigate the risks associated with ethylidene chloride's flammability, toxicity, and environmental impact. Always consult the latest Safety Data Sheet (SDS) and local regulations before use to ensure safe practices and protect health and the environment.