has replaced Project Open Data.

On January 14, 2019, the Foundations for Evidence-Based Policymaking Act ("Evidence Act"), which includes the OPEN Government Data Act, was signed into law. The Evidence Act requires the Office of Management and Budget, the Office of Government Information Services, and the General Services Administration to develop and maintain an online repository ( of tools, best practices, and schema standards to facilitate the adoption of open data practices across the Federal Government.

Archived content of Project Open Data can be accessed at its GitHub repository. You can report missing content or provide any additional feedback via GitHub or by emailing

Environmental Protection Agency Central Data Exchange

November 2, 2012
Central Data Exchange - Building an Open and Interoperable Platform for Environmental Data Sharing
U.S. Environmental Protection Agency, Office of Environmental Information, Office of Information Collection

Executive Summary

Central Data Exchange (CDX) created by the US Environmental Protection Agency (EPA) is used by Industry, State, Local Agencies, and Tribes to share environmental data. Through the use of open data standards and the service-oriented architecture (SOA) approach, CDX has become an extensible and interoperable platform for the sharing of environmental information on the national scale. Today, more than 65,000 active users and 65 environmental programs use CDX to meet their electronic reporting and data exchange needs. CDX has significantly improved the quality and timeliness of environmental data and reduced overall reporting burdens for Industry, State, Local Agencies, and Tribes. In addition, the operational cost of CDX has decreased from $30.94 in 2006 to $1.90 in 2011 on a per transaction basis due to the increase in the number of participating partners.


The environmental data collected by EPA comes from States, Local Agencies, and Tribes, and Industry. The collection and sharing of the environmental data were often done in less than efficient ways in the past. At the same time, EPA was faced with the growing information needs of environmental protection and the increasing demand for more and faster public access. Legacy computer systems that were developed to manage this information now hinder attempts at collaboration, interoperability and data sharing because they operate on incompatible platforms, databases, languages and formats. Increasing data integrity problems, rising computer maintenance costs, and the need to modernize systems outside the confines of an existing national collection system have added to the complexity of environmental data collection.


The Environmental Council of the States (ECOS) and EPA decided to meet these challenges and created a collaborative solution - the Exchange Network. EPA’s presence on the Exchange Network is CDX, a solution that supports Web-based submissions, as well as automated Web service exchanges with partners. The Exchange Network enables participants to control and manage their own data, while making it available to partners over a secure Internet connection. The Exchange Network also represents a fundamental transformation in the way that information is shared. This collaborative partnership among EPA, states, tribes, and territories across the nation supports better environmental and health-related decisions through improved access to, and exchange of environmental, health, and geographic information.

One of the cornerstones of making data exchange technology deliver information in a usable context is the establishment of open data standards across all trading partners. Data is interoperable when it can be correctly interpreted as it moves from system to system or organization to organization. EPA helps to make its data interoperable by implementing open data standards and through the registration of its data assets.

Data standards are documented agreements on representations, format, and definitions of common data. These standards are fundamental to the seamless and unambiguous exchange of data - they help improve the ability of partners (internal and external) to exchange data efficiently and accurately, and assist secondary users of data to understand, interpret, and use data appropriately. To date, EPA and its partner States and Tribes have developed 25 data standards.

In addition to data standards, EPA adopted SOA and focused on shared information technology services to prevent the traditional stove-piped approach of Program Offices having to build similar services on their own. Sharing services like quality assurance, user authentication, querying, data submission, and many others, eliminate a large portion of the development resources needed to build a data flow and in turn result in reduced cost for developing and maintaining that flow. This shift in paradigm results in the development of services that interoperate with other services, following the same open standards, as opposed to building isolated “applications” which poses more challenges with interoperability.


Currently, CDX has more than 65,000 active users. CDX supports over 65 environmental programs with their electronic reporting and data exchange needs. In addition, more than a dozen program systems are in varying stages of planning or design that will be deployed in the future. EPA has also expanded CDX to support data exchanges with other federal agencies as well as internationally.

By using improved technology and agreeing on open environmental and health data standards in which to exchange information, CDX increases the efficiency, timeliness and accuracy of data exchanges. CDX provides benefits to both EPA and other stakeholders including Industry, States, Local Agencies, and Tribes.

For EPA and Program Offices, the benefits from CDX include:

  • Decreases time to make information publicly accessible
  • Improves data quality
  • Reduces record management costs by eliminating redundant record keeping
  • Eliminates redundant infrastructure and its associated cost
  • Enables faster, lower-cost implementation of new or modified data flows
  • Integrates data to Agency data repositories
  • Establishes consistent procedures for electronic signatures
  • Assists in achieving Cross-Media Electronic Reporting Rule (CROMERR) Compliance

For Industry, States, Local Agencies, and Tribes, the benefits include:

  • Reduces overall reporting burden
  • Improves access to data
  • Reduces time and costs associated with environmental data submission requirements
  • Simplifies reporting to a single point in the Agency instead of many separate Programs
  • Allows faster securing of submission through built-in edit and data quality checks
  • Improves security and transmission of confidential business information through registration and authentication
  • Reduces burden of complying with new or changing requirements
  • Streamlines reporting through the Exchange Network and Web Services
  • Provides electronic confirmation that information was received and that the electronic form was filled out correctly

Lessons Learned

Through the implementation of the Exchange Network and CDX, EPA has learned several key lessons that have been incorporated throughout these projects:

  • Be sure to address cultural and organizational aspects through open communications and a solid governance structure among all program parties that have a stake in a shared IT services approach.
  • Successful implementation is dependent upon a combination of technology, security and data standardization.
  • Implement appropriate policies and incentives to gain momentum on an IT and data shared services approach.
  • Provide the necessary user-friendly tools for implementing open data policies into the hands of the subject matter experts so others can focus on the technology.


References to the product and/or service names of the hardware and/or software products used in this case study do not constitute an endorsement of such hardware and/or software products.