tetraetylbly

Tetraethyllead, often abbreviated as TEL, is an organometallic compound with the chemical formula Pb(C2H5)4. It is a colorless liquid, though impurities can impart a yellowish hue. Historically, its primary application was as an additive to gasoline, known as leaded gasoline. TEL was introduced as an antiknock agent, meaning it increased the octane rating of gasoline, allowing engines to operate at higher compression ratios without engine knocking or pinging. This led to improved engine performance and efficiency.

The widespread use of tetraethyllead in gasoline began in the 1920s. It was a highly effective and relatively inexpensive additive. However, as its use became ubiquitous, concerns about its environmental and health impacts grew. The lead in TEL is released into the atmosphere as particulate matter during combustion. Lead is a toxic heavy metal that can accumulate in the environment and the human body. Exposure to lead has been linked to numerous adverse health effects, particularly in children, including developmental problems, neurological damage, and behavioral issues.

Due to these concerns, a global phase-out of leaded gasoline has occurred over several decades. Many countries banned its use starting in the late 20th century, and by the early 21st century, it had been largely eliminated worldwide. While TEL is no longer used in automotive gasoline in most parts of the world, it may still find limited applications in certain aviation fuels or specialized industrial processes, though these uses are also diminishing. The legacy of TEL continues to be studied in terms of its long-term environmental contamination.