CA AB28

Requires municipal solid waste landfill operators to monitor landfill gas temperatures and take escalating corrective actions when temperatures reach sustained thresholds: 131°F triggers notification and corrective action plans; 146°F requires multiagency coordination and public notification within 4 miles; 170°F triggers potential permit suspension and emergency declarations.

Creates the Landfill Subsurface Fire Mitigation Account to collect penalties and fund mitigation for affected communities, with fines of $10,000 per day for notification failures and up to $1,000,000 per week for sustained 170°F temperatures caused by operator gross negligence.

Mandates the State Air Resources Board to amend methane emissions regulations to establish landfill gas temperature monitoring requirements, and requires CalRecycle to establish minimum guidelines for managing subsurface elevated temperature events by July 1, 2027.

Requires landfill operators to notify local enforcement agencies and CalRecycle within 48 hours of requesting federal approval for higher operating temperature limits, and to publicly disclose these requests and approvals.

Holds landfill operators liable for actual and reasonable costs incurred by enforcement agencies, and requires permits suspended due to elevated temperatures to be reinstated only after temperatures drop below 131°F for 60 consecutive days with agency consent.