Internal Revenue Code (IRC) § 4121 imposes an excise tax on domestically-mined coal when it is sold by the producer to the first purchaser. The producer is liable for the tax, but may pass it along to others through an increase in the coal's purchase price; thus, it is possible that the producer does not actually bear the burden of the tax. The Constitution's Export Clause states that "No Tax or Duty shall be laid on Articles exported from any State." Nonetheless, the coal excise tax was imposed on coal destined for export. In 1998, a federal district court held that the tax on such coal clearly violated the Export Clause. In 2000, the IRS acquiesced and stopped imposing the tax on coal that was in the stream of export when sold by the producer and actually exported. The IRC provides a process by which taxpayers who paid the unconstitutional tax may file for a refund from the IRS. The claim must be made within three years from the time the excise tax return was filed or two years from the time the tax was paid, whichever is later. The producer that paid the tax has first claim to any refund. Exporters may claim refunds only "if the person who paid such tax [i.e., the producer] waives his claim to such amount." A taxpayer filing a refund claim must establish that it: (1) did not include the tax in the coal's purchase price or otherwise collect the tax from the purchaser; (2) has repaid, in the event the tax burden was shifted, the amount of tax to the ultimate purchaser; or (3) has filed the ultimate purchaser's written consent for the refund with the IRS. Taxpayers seeking a refund in court must first file a timely refund claim with the IRS and then wait six months, unless the IRS makes a determination prior to that date, before bringing suit. Some coal producers and exporters brought suits under the Export Clause seeking damages from the United States in the amount of unconstitutional coal excise taxes they paid. They brought the suits in the Court of Federal Claims, arguing that it had jurisdiction to hear them under the Tucker Act. That act grants the court jurisdiction over "any claim against the United States founded either upon the Constitution, or any Act of Congress or any regulation of an executive department, or upon any express or implied contract with the United States, or for liquidated or unliquidated damages in cases not sounding in tort." Taxpayers used these suits as a way to bypass two limitations in the IRC refund process. First, the Tucker Act has a longer statute of limitations—six years from the time the tax is paid —than the IRC. This allowed taxpayers to seek damages for taxes paid in the several years preceding the years for which they could receive IRC refunds. Second, the Tucker Act, unlike the IRC, does not give priority to producers' claims. Thus, it potentially allowed parties farther down the supply chain (e.g., exporters) to bring claims alleging they deserved damages because they bore the economic burden of the tax. A threshold issue has been whether the Court of Federal Claims could hear these suits. The Tucker Act only confers jurisdiction—it "does not create any substantive right enforceable against the United States for money damages." Thus, the substantive right must be found in another source of law. One question has been whether the Export Clause provides a right to monetary damages when the government violates it. If the answer is yes, a related question has been whether such a claim could be made independently of an IRC refund claim. If not, then taxpayers would need to meet the IRC's more stringent requirements. In Cyprus Amax Coal Co. v. United States , the Court of Appeals for the Federal Circuit addressed the jurisdictional question. The court's holding had two components. The first was that the Export Clause was a money-mandating provision, as required for Tucker Act jurisdiction. The second was that a cause of action founded in a violation of the Export Clause was self-executing. This meant the Clause provided a separate cause of action so that a taxpayer could bring a suit for damages independent of an IRC administrative refund claim. In a later case, the court clarified that the Export Clause was not a money-mandating provision for all parties seeking coal excise tax refunds. In that case, the court held that the Tucker Act did not provide jurisdiction to hear the claim of an ultimate purchaser who alleged it had paid the tax through higher coal prices but did not directly pay the tax to the government. After the Cyprus Amax decision answered the question of its jurisdiction under the Tucker Act, the Court of Federal Claims heard several cases brought by coal brokers and ultimate purchasers that it dismissed due to lack of constitutional standing. To have standing, "[a] plaintiff must allege personal injury fairly traceable to the defendant's allegedly unlawful conduct and likely to be redressed by the requested relief." The parties alleged that they were injured by the government's unconstitutional imposition of the coal excise tax because the burden of the tax was shifted to them by coal producers charging higher prices for coal. The Court of Federal Claims found the requisite causal relationship between this injury and the government's action to be lacking. This was because it was the independent actions of the producers that determined whether the parties paid any amount of the unconstitutional tax. As noted, the Federal Circuit Court of Appeals also raised a barrier to claims by non-producer parties by holding there was no Tucker Act jurisdiction to hear the claim of an ultimate purchaser who did not actually pay the tax to the government. In a 2008 decision, United States v. Clintwood Elkhorn Mining Co. , the Supreme Court held that taxpayers seeking refunds for the unconstitutionally-imposed coal excise tax must comply with the IRC refund process. The taxpayers in that case had filed administrative refund claims for the three tax years open under the IRC's statute of limitations and filed suit in the Court of Federal Claims seeking the amount of taxes paid for the three previous years that were open only under the Tucker Act's longer limitations period. The Court of Appeals for the Federal Circuit had allowed their suit and denied the government's request to reverse its Cyprus Amax holding. The appeals court said that the issue of whether taxpayers could bring suit under the Export Clause without complying with the IRC refund scheme had been "fully aired" in Cyprus Amax and it could "discern no basis for reopening this question." The Supreme Court, in a unanimous decision, held that the plain language of the relevant IRC provisions, § 7422 and § 6511, clearly required that the taxpayers file a timely refund claim with the IRS before bringing suit. The Court stated that it had basically decided the issue in a 1941 case where it had reasoned that the Tucker Act's statute of limitations was simply "'an outside limit'" which Congress could shorten in situations requiring "'special considerations,'" such as tax refunds because "'suits against the United States for the recovery of taxes impeded effective administration of the revenue laws.'" The Court noted that it had explained in that case that the IRC's refund provisions would have "'no meaning whatever'" if taxpayers who did not comply with those provisions could still bring refund suits under the Tucker Act. The Court did not address whether the Export Clause provided a cause of action that could be brought under the Tucker Act, finding that the IRC refund provisions would apply regardless of the answer to that question. Noting that it was clear from its past cases that unconstitutionally-collected taxes could be subject to the same administrative requirements as other taxes, the Court rejected the taxpayers' argument that something unique about the Export Clause required different treatment. The Court explained that while the government may not impose unconstitutional taxes, it may create an administrative process to refund such taxes because of its "'exceedingly strong interest in financial stability,'" regardless of whether the tax violated the Export Clause or some other provision of the Constitution. The Court also rejected the taxpayers' claim that the IRC refund scheme could not apply to facially unconstitutional taxes, finding the plain language of IRC § 7422 clearly included such taxes. There appear to be two primary impacts of the Court's decision in Clintwood Elkhorn . The first is that taxpayers seeking refunds for the unconstitutionally-imposed coal excise tax must file refund claims with the IRS, subject to the IRC's limitations. Thus, taxpayers are subject to the shorter statute of limitations and non-producer parties may only seek a refund if the producer who paid the tax has waived its right to the refund. Second, the Court's analysis seems broadly applicable to refund claims in general, including those based on violations of other constitutional provisions. The Senate-passed version of H.R. 6049 , § 114 (Energy Improvement and Extension Act of 2008) and H.R. 7060 , § 114 (Renewable Energy and Job Creation Tax Act of 2008), passed by the House on September 26, 2008, would provide an alternative administrative procedure for refunding the unconstitutionally-imposed coal excise tax. In order to claim a refund, a coal producer would have to establish that it, or a related party, exported coal produced by it to a foreign country or shipped it to a U.S. possession, or caused such export or shipment, through means other than by an exporter that met the proposal's requirements to file a claim. A producer with a favorable court judgment related to the excise tax's constitutionality would be deemed to meet this requirement. An "exporter" would have to establish that it exported coal to a foreign country or shipped it to a U.S. possession, or caused such export or shipment. Additionally, the producer or exporter would need to (1) have filed a return between October 1, 1990, and the date of the act's enactment, and (2) file a claim for the refund within 30 days of the enactment.