Tetrachloroethylene, scientifically known as tetrachloroethene or PCE, is an organochlorine compound with the chemical formula C2Cl4. It presents as a colorless, dense liquid with a characteristic sweetish odor, readily recognizable by most individuals at relatively low concentrations. Its stability, non-flammability, and excellent solvency for organic materials are the primary reasons for its widespread adoption in industries such as dry cleaning and metal degreasing. The chemical structure, with all four hydrogen atoms of ethene replaced by chlorine atoms, contributes to its unique properties, including resistance to hydrolysis and relative inertness compared to other chlorinated solvents.

From a safety perspective, tetrachloroethylene is recognized as a substance that requires careful handling. While its non-flammable nature reduces fire risks, inhalation of high concentrations of its vapors can lead to anaesthetic effects and respiratory irritation. Long-term or high-level exposure has been linked to potential adverse health effects, including impacts on the nervous system, liver, and kidneys. Consequently, it has been classified by regulatory bodies and scientific organizations, such as the International Agency for Research on Cancer (IARC), as a probable human carcinogen (Group 2A). This classification underscores the importance of stringent safety protocols, adequate ventilation, and personal protective equipment (PPE) when working with tetrachloroethylene, whether in industrial settings or professional dry cleaning operations.

The regulatory environment surrounding tetrachloroethylene is dynamic, with increasing efforts to limit its use and promote safer alternatives. In many regions, occupational exposure limits have been established to protect workers, and there is a continuous push to minimize environmental release. Understanding the specific CAS number, 127-18-4, is vital for accurate identification and compliance with chemical management regulations. As industries adapt to these changes, research into the properties and applications of tetrachloroethylene continues, balanced against the urgent need for more sustainable and health-conscious chemical solutions. The future likely involves a gradual phase-out of PCE in many applications, replaced by compounds that offer comparable performance with a reduced risk profile.