The Ethyl Corporation primarily, they had to quickly diversify and adjust their business model as a result of the US phase out of tetraethyllead. They managed to stem some of the bleeding by simply just...selling the rest to other countries before they instituted their own restrictions on leaded gas (which tells you how ethically sound said business was) but this was a massive change at the time considering just about every vehicle used leaded gas even if it was a slow rollout.
Who lost their job when leaded gas was banned? A web search did not give me any examples.