A system and method for covering a cellar at a wellhead to prevent and control fluids and gases from the cellar. The covering includes a mat that circumscribes a wellhead tubular that projects upward from the cellar. A split seam in the mat extends radially from the opening to the mat outer periphery which allows the mat to be placed around the wellhead tubular. A fastener joins the ends of the mat that meet at the split seam. The mat includes a collar, which mounts to the mat along the opening and extends axially away from an upper surface of the mat. The collar is secured to the wellhead tabular with a strap. Two discharge lines project through the mat into the cellar, one for pumping into the cellar, and one for withdrawing fluid that has collected in the cellar.