IL SB3393

Requires owners/operators of active municipal solid waste landfills with 200,000+ tons of waste in place to calculate and annually report methane generation rates to the Illinois Environmental Protection Agency.

Mandates installation of gas collection and control systems for landfills with calculated methane generation rates of 664+ metric tons, unless owners demonstrate no measured methane concentrations ≥200 parts per million over 4 years.

Establishes surface methane concentration limits of 200 parts per million (instantaneous monitoring) or 25 parts per million average (integrated monitoring), with required corrective actions for exceedances.

Requires gas control devices to achieve 99% methane destruction efficiency, with flares allowed until January 1, 2029, and annual source testing for compliance verification.

Mandates annual reporting, record-keeping for monitoring and operations, closure notifications, and allows landfill operators to request alternative compliance measures subject to Agency approval within 120 days.