A link to a historical analysis of lead is insufficient for substantiating an assertion that peer reviewed studies confirmed its safety a priori. It was "approved" by fossil fuel companies insofar as it was useful in providing anti-knocking protection in primitive internal combustion engines, but the dangers of tetra-ethyl lead were known within years of its widespread introduction into gasoline. Ergo it was not "peer reviewed and approved" in the sense you're suggesting.
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