For the past year, ProPublica has been documenting the state of toxic pollution left behind by the military across the U.S. As part of this investigation, we acquired a dataset of all facilities that the Department of Defense considers contaminated. Today we used the data to publish an interactive news application called Bombs in Your Backyard. Here’s how you can use it to find hazardous sites near you — and what, if anything, is being done to remedy the pollution.

The data, which has never been released before, comes from the Defense Environmental Restoration Program, which the DOD administers to measure and document cleanup efforts at current and former military locations.

There are a lot of great local investigative stories waiting to be done with the data. This reporting recipe is meant to help you find and report ones near you.

Why You (and Your Readers) Should Care

• There are more than 40,000 hazardous sites across the country polluted by U.S. military operations, affecting a total amount of land larger than the entire state of Florida. Some of these sites are probably near you and you may not even know it.

• Many of these sites have extensive groundwater and soil pollution, or present a risk of exploding bombs and munitions, even if they are open to the public. Some have been converted to parks and wildlife reserves and even housing developments.

• Many sites were part of old defense facilities that have long since shut down, and may not be known locally, even though a risk of exposure to contaminants may still be present.

• Even sites where the DOD says it has already completed its response can present an ongoing threat or risk to the public.

• While the data pinpoints a precise location, contamination from that location may well affect a much larger area, including public and private lands and the water supplies beneath them. You may want to investigate environmental concerns in an area surrounding a defense site for connections to the pollution there.

Background Reading

• Open Burns, Ill Winds — The Pentagon’s handling of munitions and their waste has poisoned millions of acres, and left Americans to guess at the threat to their health.

• How Military Outsourcing Turned Toxic — Fraud. Bribery. Incompetence. The military’s use of contractors adds to a legacy of environmental damage.

• Kaboom Town — The U.S. military burns millions of pounds of munitions in a tiny, African-American corner of Louisiana. The town’s residents say they’re forgotten in the plume.

Important Definitions

Before you start thinking about how you can use this data to report on facilities in your area, you should know some definitions.

• An installation, as the DOD means it, is a property formerly or currently owned by a DOD organization, like a military base, bombing range or munitions plant.

• Within installations are specific cleanup sites, which are the contaminated areas of an installation. An installation can have one site, or hundreds.

• Response Complete means the DOD cleanup actions are complete. It does not necessarily mean that a site has been cleaned up, or that there is no longer an environmental risk. In some cases, “completed” sites are simply restricted or fenced off to keep the public away. In other cases, the DOD may have concluded that no cleanup was required by law or was necessary. Note that long-term monitoring or other restrictions may still be in place after a site has reached “Response Complete” status.

• The DOD evaluates the risk posed by contaminated sites relative to all others in the cleanup program in order to prioritize which sites get cleaned up first. A site designated as “high risk” is considered so by DOD as compared to other sites in the program. When designating risk, the DOD takes into account the hazards of contaminants and where and how they might affect humans and the environment. The DOD uses a different designation for sites that contain unexploded ordnance or discarded military munitions. We simplify the two scales into one. You can read more about the risk designations in our full methodology under “Risk Levels.”

Story Ideas

• Which land near you is contaminated by former military activities? Millions of acres across the country present a risk to the public through exposure to polluted water, soils or unexploded munitions. They may be closer to you than you think. Use the app’s location search bar to see installations near you, or select the “Use My Location” button to be located automatically.

• You’ll need to give our site permission to access your location data. (Don’t worry, we won’t store it.) The app will also display a list of the closest “high risk” sites near you.

• Have groundwater resources near you been polluted by former military activities? Water pollution is one of the most serious, and most common, lingering effects of past military activities and it’s invisible. But this data can alert you to sites with ongoing risks. The app lists if a site’s groundwater or surface water is known to have been contaminated.

• Former military sites are littered with unexploded ordnance in places which are now public parks and residential areas. Finding explosives is uncommon, but it’s possible. These sites are marked with a bomb icon in the interactive database.

• Which lands have restricted access and why? Maybe you know about a former defense site near you, even one that has been cleaned up. Many former military sites have been certified as “Response Complete” but still carry restrictions that limit what people can or should do near these sites to stay safe. Just because the DOD is no longer attending to pollution doesn’t mean that there is no longer a public risk. These sites are labeled with “No Access” in the app.

• The map pinpoints a precise location identified with a cleanup site, but the affected area may be much larger, even spreading off of Defense Department lands. Sites in Washington, D.C., and Massachusetts, for example, affect hundreds of acres in residential areas far from the point of contamination. The map should serve as a starting point to investigate known sources of pollution that could have a broader effect on your area.

• There may be historical Defense Department sites near you that you never knew about. While the contamination at these sites may have been fixed, the map can also lead to new insights into local historical activities and the role parts of your community played in past wars.

• What are the facilities in my state that my readers should know about? If you look along the left of the main page you’ll see a list of states and how many installations with medium and high risk sites we found in each. If you click on the name of your state, you can see lots more about the facilities there, including which installations have the most high risk sites.

To find out more about the contaminants at a site near you, you can contact your state’s hazardous waste program and/or environmental agency. The federal Environmental Protection Agency (which can also be a source in its own right) keeps a list of state agencies here. If a site has been examined for health risks in the past, you can find more information by consulting the Agency for Toxic Substances and Disease Registry. The ATSDR also keeps information on many of the most common toxic contaminants found at military sites.

How We Got and Prepared the Data

We got the data from the Department of Defense via a public records request. It arrived as 93 separate relational database tables, with extensive documentation.

To prepare the data for the interactive map, we first cleaned it. We excluded from the map any installations whose latitude and longitude data field weren’t in the same state as the one listed in the “state” data field for that site’s record.

We hand-checked 550 individual site coordinates, including all the ones for sites deemed “high risk.” We removed six of them from the map that we found to be erroneous. There were another 30 instances where we could not verify the accuracy of the latitude and longitude. With this very low percentage of error, we are confident in the accuracy of site locations. If you notice a wrong location, please contact us.

You should read our complete methodology to understand the data and what we did to clean and display it.

We hope this interactive database is useful and that you find great stories in it. If you end up publishing anything in the data, please let us know!