Outline a common method for decommissioning a UST.

The method of decommissioning a UST involves important procedures to ensure safety and environmental compliance. Cleaning and emptying the tank is critical to remove any residual product and vapors that could pose hazards. After this cleaning phase, the tank can either be removed from the ground entirely or filled with inert material if removal is not feasible.

This approach minimizes the environmental risks that could arise from potential leaks or contamination, ensuring that hazardous materials are properly managed. The regulatory standards outline these processes clearly, emphasizing the importance of thorough decommissioning to maintain safety and prevent contamination of the surrounding area.

Other options do not effectively address safety concerns. Sealing the tank with a lid might leave hazardous substances or vapors inside, which can lead to safety issues or environmental hazards. Painting the exterior does not address the internal contents or structural integrity of the tank, and simply placing the tank in storage fails to deal with the potential pollution risks if the tank is still containing hazardous materials. Thus, option A stands out as the correct and comprehensive method for decommissioning a UST.