Abstract: A gas trap system for releasing gas-phase fluids is provided herein. The gas trap system is designed to reside within a return fluids tank, such as at a drill site. The gas trap system first includes a gas trap. The gas trap is configured to agitate drilling fluids in the return tank, and then to release gases during agitation. Liquids are circulated and released through a liquids exhaust port while gases are released through a gas exhaust port near the top of the gas trap. The gas trap system is configured to float along vertical guide rods in response to changes in height, weight and viscosity of the drilling fluids in the return tank. A method of capturing gaseous phase fluids from a fluid return is also provided herein. The fluid return is preferably drilling fluids at a drill site.