By Taiga Takahashi

The U.S. EPA recently opened access to NEPAssist, an online Geographic Information System program that “facilitates the environmental review process and project planning in relation to environmental considerations” under the National Environmental Policy Act (NEPA) and other environmental assessment statutes. The program is available at the EPA website and is open to the public.

NEPAssist has the normal features of other publicly available web-based mapping services, such as nationwide street maps in two and three dimensions, in addition to aerial and satellite views.

Map overlays
NEPAssist draws environmental data from EPA and other government databases at the user’s request and provides an immediate overview of various environmental assessment indicators for a user-defined area of interest. These overlays include, for example:

  • EPA facilities, such as brownfields, Superfund sites, toxic release points, and hazardous waste sites;
  • Water monitoring stations;
  • Community points of interest, such as schools, churches, and hospitals;
  • Railroads and airports;
  • Water body features, such as impaired streams and water bodies under the Clean Water Act, aquifers, and watersheds;
  • Clean Air Act nonattainment areas for the ozone, lead, and annual and 24-hour particulate matter standards;
  • Borders of interest, such as zip codes, congressional districts, cities, towns, counties, states, federal lands, and EPA regions;
  • Demographic information;
  • Other important land-use information, such as wetlands areas, FEMA flood hazard designations, topographical overlays, and development and land cover overlays.

Built-in data analysis
NEPAssist offers a variety of other useful data analysis and comparison features.

  • Source data access: for certain information, the original source data or report is available instantly. For example, highlighting an impaired water body gives access to the original TMDL source report.
  • Drawing features and customized reports: the user can draw project boundaries, and NEPAssist will produce reports that will show distances to important points of interest for environmental planning, including distances to wetlands, Superfund sites, etc. as described above. These reports include state-specific requirements, as well as requirements pertaining to federal law.
  • Environmental Justice reports: NEPAssist also provides Environmental Justice reports. These reports compare project-specific demographic characteristics to County and national averages.

Example NEPAssist Report


NEPAssist is still a work in progress, but EPA is planning to revise and update it according to user feedback. Some limitations and plans for further development include:

  • Saving data: each time a user leaves the website and returns, he/she will have to redraw the study area.
  • Not all federal environmental data has been incorporated into NEPAssist, but EPA plans to supplement current data and add new data in the future.
    • More complete data: For example, wetlands information is available through NEPAssist, but it is incomplete. EPA is in the process of fully incorporating wetlands data into NEPAssist.
    • New data: ESA-related data (for example, presence of listed species, critical habitat, etc.) is not (yet) available through NEPAssist. EPA stated a desire to add this information in the future.

While still in the development stage, NEPAssist offers relatively easy and consolidated access to federal government environmental data. Planners, decision-makers, and the public should find NEPAssist to be a valuable and convenient tool in the environmental review process.