Described herein are embodiments of a control system that automatically (1) determines whether a gas extraction system is in a state in which landfill gas is being released into the atmosphere, and (2) automatically controls landfill gas flow to mitigate, prevent and/or stop the release of landfill gas. The control system may control a valve to control flow of landfill gas through well piping of the gas extraction system. The pressure of landfill gas in the well piping at a location upstream of the valve may indicate whether there is a risk of landfill gas being released into the atmosphere. The control system may adjust a position of the valve in response to determining that the pressure at the location upstream of the valve indicates that there is a risk of landfill gas being released into the atmosphere.