Oil and gas companies and big business trade associations were among those keeping up donations after Manchin announced he would not run for re-election.
A coalition of companies like Cargill and Chevron hired new lobbyists as it works to convince policymakers that so-called "renewable natural gas" should get government subsidies.
Environmental groups warn that hydrogen fuel produced with fossil gas could entrench the oil & gas industry for decades.
Republican lawmakers who wrote bills that were wrapped into the H.R. 1 energy package own stock in Marathon Oil, Chevron, and family-held oil and gas drilling operations.