Agencies promulgate rules to implement statutorily authorized regulatory programs. These rules, although established by an administrative agency, maintain the force and effect of law. To be able to promulgate rules, an agency must be granted by Congress the power to do so, either explicitly or implicitly, through statute. To control the process by which agencies create these rules, Congress has enacted statutes, such as the Administrative Procedure Act (APA), that dictate what procedures an agency must follow to establish a final, legally binding rule. Often, the organic statute that allows an agency to implement a program through rulemaking may be ambiguous. The agency must then interpret the ambiguous terms of the statute in order to establish the regulatory program. The Supreme Court, in Chevron U.S.A., Inc. v. Natural Resources Defense Council , established the Chevron test, which requires courts to defer to an agency's interpretation of an ambiguous statute if the agency's interpretation is reasonable. The Chevron test has been a staple in the canon of administrative law since it was handed down from the Court in 1984. However, what happens if an agency's regulation is ambiguous? The Supreme Court's decision from Bowles v. Seminole Rock & Sand Co. addresses when an agency's regulation, as opposed to its organic statute, is ambiguous. Seminole Rock deference—which provides an agency judicial deference when an agency interprets its own regulations—arguably has become an equally important, if slightly less recognizable, canon of administrative law as the Chevron test. Just as statutes enacted by Congress occasionally lack clarity, sometimes regulations enacted by administrative agencies can be unclear. The Supreme Court ruled in Seminole Rock that a court must accept an agency's interpretation of its own regulations unless it is "plainly erroneous." Legal scholars have noted that this deference has benefits and drawbacks. By enabling agencies to interpret their own regulations, agencies are provided with flexibility to enact broad rules and refine them as specific circumstances arise. This process may help agencies administer complex regulatory schemes with greater efficiency. Furthermore, courts often note that the agency—as opposed to a reviewing court—has a better understanding of what the regulation is intended to accomplish. On the other hand, it may be troubling that the author of these legally binding rules also possesses the power to interpret the meaning of those regulations when the text is not clear. Furthermore, imprecise regulations can lead regulated industries to lack the necessary knowledge of how a regulation will be interpreted or enforced. Without concrete knowledge of the meaning of a regulation, a regulated entity will not easily be able to ensure that its behavior and practices conform to the required standards. Indeed, although Seminole Rock deference has been a long-standing tenet of administrative law—the case was decided in 1945—at least three Justices of the Supreme Court have recently questioned whether this deference is still appropriate. In the recent Supreme Court opinion from Decker v. Northwest Environmental Defense Center , Justice Scalia attacked the concept of Seminole Rock deference directly, noting "[f]or decades, and for no good reason, we have been giving agencies the authority to say what their rules mean ..." Justices Roberts and Alito, in a one-page concurrence, simply noted that "it may be appropriate to reconsider the principle" of Seminole Rock deference. Justice Thomas also appears to have previously questioned whether continued reliance on Seminole Rock is appropriate. Although the holding in Seminole Rock remains in place, these opinions reflect the possibility that the Court may be willing to consider whether this judicial deference should remain in effect in a future case. Although the APA prescribes the procedures that agencies must undertake in order to promulgate agency rules, there is no provision within the APA that requires agency regulations to meet any standard of clarity or precision. During the rulemaking process, persons and organizations that are affected by proposed rules may submit comments to the agency (if the agency is using "notice and comment" rulemaking procedures) or present evidence (if the agency must use the "formal" rulemaking procedures). During this process, those submitting comments or presenting evidence could raise issues relating to the clarity of the proposed rule, but there are no set standards that ensure an agency will enact clear regulations. The Supreme Court has noted that "[t]he APA does not require that all the specific applications of a rule evolve by further, more precise rules rather than by adjudication." This principle allows an agency to adopt broad guidelines, established by a rulemaking, that can then be further clarified through individualized adjudication proceedings. The reasoning behind this is that courts do not believe that agencies should have to engage rulemaking procedures that may be lengthy and demanding to be able to capture every instance in which a rule will be applied. However, what happens when a regulated entity believes that it has complied with a regulation, but the agency interprets the rule in a different manner? In Bowles v. Seminole Rock & Sand Co. , the Court declared that agencies are entitled to significant deference when they are interpreting their own regulations. The Court applied a "plainly erroneous" standard—if the agency's interpretation is plausible, it will be given effect. When determining the meaning of an administrative regulation, the Court announced that [A] court must necessarily look to the administrative construction of the regulation if the meaning of the words used is in doubt.... [T]he ultimate criterion is the administrative interpretation, which becomes of controlling weight unless it is plainly erroneous or inconsistent with the regulation ... [a court's] only tools, therefore, are the plain words of the regulation and any relevant interpretations of the Administrator. The decision in Seminole Rock arose from a dispute concerning the interpretation of the Maximum Price Regulation No. 188, which was promulgated by the Office of Price Administration pursuant to the Emergency Price Control Act of 1942. The rule—which established price ceilings—commanded that a seller could not charge a higher price for delivery of any article than the seller's highest price charged during the month of March 1942. In order to determine what qualified as the "highest price charged during March, 1942," the regulation established that it should equal "the highest price which the seller charged to a purchaser of the same class for delivery of the article or material during March, 1942." Seminole Rock & Sand Company had delivered crushed rock to a purchaser in March 1942 for a price of 60 cents per ton; however, Seminole Rock had charged the purchaser on this sale several months earlier. Seminole Rock argued that because there was no charge in March 1942, but only a delivery, its price ceiling should not be set at 60 cents per ton. The Administrator argued that the rule is satisfied whenever there has been a delivery of the specified articles during that month, regardless of when the sale actually occurred. The Court looked to the agency's previous interpretations of the rule, and determined that the agency's interpretation of its own rule should be controlling "unless it is plainly erroneous or inconsistent with the regulation." Thus, although there could be two possible readings of the regulation, the agency's interpretation was not plainly erroneous and, therefore, was determined to be controlling. With the Court's decision, the precedent for giving judicial deference to an agency's interpretation of its own rules was set. Since Seminole Rock , the Court has continued to follow this "plainly erroneous" standard. In Thomas Jefferson Univ. v. Shalala , the Court stated, "[w]e must give substantial deference to an agency's interpretations of its own regulations. Our task is not to decide which among several competing interpretations best serves the regulatory purpose." The Court reiterated that the agency's interpretation should be followed unless it is plainly erroneous or clearly inconsistent with the agency's "intent at the time of the regulation's promulgation." The Court has clearly stated that "the power authoritatively to interpret its own regulations is a component of the agency's delegated lawmaking powers." Even more recently, in 2008, the Court again stated, "[j]ust as we defer to an agency's reasonable interpretations of the statute when it issues regulations in the first instance, the agency is entitled to further deference when it adopts a reasonable interpretation of regulations it has put in force." This statement may suggest that Seminole Rock deference is even more deferential than what is provided to an agency during the application of the Chevron test. Although this judicial deference is substantial, it is not without limit. In some circumstances a court must refuse to defer to an agency's interpretation. Courts will not defer to an agency's interpretation if the regulation itself is clear, if the agency suddenly changes its interpretation, or if the agency's regulation merely "parrots" the statutory language. Finally, courts generally prevent agencies from levying punitive fines against regulated entities if the regulated party could not have reasonably known how the agency planned to interpret the regulation. These exceptions are discussed in further detail below. In order for an agency's interpretation to be granted Seminole Rock deference, the agency's regulation must first be ambiguous. As the Court noted in Seminole Rock , the agency's interpretation should only be controlling if it is not "plainly erroneous or inconsistent with the regulations." Therefore, if the regulations are clear, then the agency is not permitted to interpret them in any manner that suits its immediate needs. The Court ruled in Christensen v. Harris County that Seminole Rock deference is "warranted only when the language of the regulation is ambiguous.... To defer to the agency's position [in this circumstance] would be to permit the agency under the guise of interpreting the regulation, to create de facto a new regulation." In Christensen , the regulation in question stated that an agreement between an employer and employee " may include other provisions governing the preservation, use, or cashing out of compensatory time ..." The agency purported to "interpret" this regulation as requiring an agreement to address these issues.