Air Pollution:

EPA Should Improve Oversight of Emissions Reporting by Large Facilities

GAO-01-46: Published: Apr 6, 2001. Publicly Released: May 7, 2001.


John B. Stephenson
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The Environmental Protection Agency (EPA) performs limited oversight of states' processes for verifying the accuracy of large industrial facilities' emissions reports. EPA's data show that most emissions determinations from large sources are based on generic emissions factors. Although EPA allows facilities to estimate their emissions in this manner, EPA officials generally consider direct methods to be more reliable. The accuracy of these reports is important because they influence (1) the financing of states' regulatory programs through fees and (2) the development of emissions inventories, which, in turn, help regulators to develop control strategies and establish permit limits. Furthermore, steps taken to assess the accuracy of these reports, such as more thoroughly reviewing the supporting information, could improve compliance with Clean Air Act requirements. For example, a more thorough review of the information underlying a facility's emission reports, or a more systematic comparison of these reports over time, could identify increased emissions. Such indications could, in turn, trigger a review of compliance with new source review requirements, an area in which EPA found widespread noncompliance in four industries. In the four states that GAO reviewed, the states that had done the most detailed reviews found widespread inaccuracies. Although it is taking steps to improve its overall compliance monitoring strategy, EPA does not plan to evaluate states' processes for verifying emissions reports from large facilities.

Status Legend:

More Info
  • Review Pending-GAO has not yet assessed implementation status.
  • Open-Actions to satisfy the intent of the recommendation have not been taken or are being planned, or actions that partially satisfy the intent of the recommendation have been taken.
  • Closed-implemented-Actions that satisfy the intent of the recommendation have been taken.
  • Closed-not implemented-While the intent of the recommendation has not been satisfied, time or circumstances have rendered the recommendation invalid.
    • Review Pending
    • Open
    • Closed - implemented
    • Closed - not implemented

    Recommendation for Executive Action

    Recommendation: To help ensure the accuracy of facilities' emissions reports, the Administrator of EPA should evaluate states' programs to determine whether they have adequate mechanisms in place for verifying the accuracy of the reports. If the results of these reviews identify inadequacies, the Administrator should work with the states to improve their processes in order to provide reasonable assurance that facility reports are subject to thorough review.

    Agency Affected: Environmental Protection Agency

    Status: Closed - Implemented

    Comments: According to EPA data, emissions factors (average emissions rates that have been calculated for various combinations of industrial processes, raw materials, and other factors) are used, nationally, for about 80 percent of emissions reports, instead of direct measurements of emissions. EPA has revised the emissions factor program (1) to better account for the uncertainty inherent in using emissions factors, (2) to expedite the data transfer necessary to develop and approve emissions factors, and (3) to consolidate and facilitate the retrieval of information on emissions factors. These steps will make emissions factors, and thereby emissions reports, more accurate.

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