; United States city average), rounded up to the next whole dollar amount. (d) Refund The Secretary shall provide a refund equal to the tax per metric ton of carbon dioxide or carbon dioxide equivalent for the capture and permanent sequestration of greenhouse gas emissions or from the use of a fossil fuel in manufacturing which does not result in the emission of a greenhouse gas in a manner that can be reasonably assumed to permanently sequester the greenhouse gas content of the fossil fuel. 4692. Border adjustments (a) Exports In the case of any good exported from the United States, the Secretary may provide an equivalency refund to the person exporting such good equal to the cost associated with the tax imposed in section 4691. (b) Imports In the case of any good imported into the United States that would have had an increased cost imposed by section 4691 had that good been produced in the United States, the Secretary may impose an equivalency fee on the person importing such good equivalent to the tax that would have been imposed under section 4691 at any point in the supply chain of that good, had that good been produced in the United States. (c) Regulatory authority The Secretary shall consult with the Administrator of the Environmental Protection Agency, the United States Trade Representative, and the Secretary of Energy in establishing rules and regulations implementing the purposes of this section. 4693. Definitions and other rules (a) Definitions For purposes of this subchapter— (b) Carbon dioxide equivalent The term carbon dioxide equivalent means, for each greenhouse gas, the quantity of greenhouse gas that the Administrator of the Environmental Protection Agency determines makes the same contribution to global warming as 1 metric ton of carbon dioxide. (c) Greenhouse gas The term greenhouse gas means any of the following: (1) Carbon dioxide. (2) Methane. (3) Nitrous oxide. (4) Sulfur hexafluoride. (5) Hydrofluorocarbons. (6) Perfluorocarbons. (d) Regulations The Secretary shall prescribe such