IL HB4773

Creates the Illinois Climate Change Superfund as a special fund in the State treasury to finance climate adaptation projects including flood control infrastructure, urban heat reduction, water management systems, and ecosystem restoration

Requires at least 40% of Fund expenditures to directly benefit disadvantaged communities facing climate change impacts

Holds "responsible parties" liable for payments into the Fund, defined as entities responsible for more than one billion tons of greenhouse gas emissions from fossil fuel extraction or refining during 2000-2024

Directs the Illinois EPA to adopt rules within one year for identifying responsible parties, calculating their proportional share of emissions, issuing cost recovery demands, and disbursing funds for qualifying projects

Allows responsible parties to pay their assessed amounts in equal annual installments over 5 years (minimum 20% per year)