Progressive Democrats want to require the nation’s largest fossil fuel companies to finance $500 billion in climate efforts over the next decade.

More than 40 Democrats, in a letter Friday to House leaders, are urging House leaders to create this new climate fund in the $3.5 trillion tax and spending plan that forms the core of President Joe Biden’s economic agenda. Companies affected by the proposal would include Exxon Mobil Corp.Royal Dutch Shell PlcChevron Corp., and BP Plc.

“As Congress fleshes out the details of this legislation, we believe there is a crucial opportunity to design revenue-raising measures that not only offset the critical investments we need, but that also align with the values, goals, and urgency with which we must tackle challenges like climate change,” they wrote.