| > The first clinical studies that showed it was toxic were in 1969. We knew it was dangerous within a year of it being introduced, even if we didn't publish widespread clinical studies before the 60s. Its creator, Thomas Midgley Jr, was diagnosed with lead poisoning multiple times. > Warnings about the toxicity of tetraethyllead came to Midgley from various sources. The letter of Erich Krause concerning its toxic effects, quoted in part in part 1,2 written on November 30, 1922, to George Calingaert (then at M.I.T.) was forwarded to Midgley in December 1922 by W. G. Whitman, Assistant Director of the M.I.T. Research Laboratory of Applied Chemistry. However, despite his own health problems and these early warnings, Midgley did not appear to be overly concerned about the health issues associated with the handling and use of tetraethyllead. https://pubs.acs.org/doi/10.1021/om030621b There's also some discussion at https://en.wikipedia.org/wiki/Tetraethyllead#Initial_controv... suggesting that early studies may have been suppressed by the lead industry. > In the years that followed, research was heavily funded by the lead industry; in 1943, Randolph Byers found children with lead poisoning had behavior problems, but the Lead Industries Association threatened him with a lawsuit and the research ended. |