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Overview

Tetraethyl lead is an extremely toxic substance that, in minute quantities, improves the efficiency and performance of internal combustion engines. Recognizing these qualities, General Motors began working on a production process in the early 1920s and soon turned development over to DuPont, which utilized expertise developed in the Dyestuffs Department.

In 1924 the Standard Oil Company developed a lower-cost chlorine production process which was soon adopted by all TEL producers, including DuPont. The government halted production of TEL when Standard Oil’s process led to five worker deaths and 35 illnesses. Learning from Standard Oil’s problems, DuPont developed a safer, controlled process that received the U.S. Surgeon General’s approval. DuPont resumed production and by the mid-1930s TEL was nearly as profitable as dye production despite much lower sales volume. By arrangement with the Ethyl Company, DuPont was the sole producer of TEL until the late 1940s, largely because of its expertise in manufacturing the dangerous substance on a large scale safely. When the GM and Standard Oil patents expired in 1948, DuPont withdrew from the arrangement and began marketing TEL itself.

Profits and production peaked in the early 1970s and then began to decline, affected by growing concern over air pollution and increased use of catalytic converters. DuPont phased out U.S. production because TEL came under increasing regulation after the Environmental Protection Agency found residual lead from automobile emissions a potential health hazard.

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