It looks sort of like a collection of colorful gumballs, scattered across the U.S. Some parts of the country have more gumballs than others — the coasts of Louisiana and Texas have quite a collection going — but so does Bradford, Pa.; Purcell, Okla.; Belden, N.D.; and Camden, N.J. In other parts of the country you can see what looks almost like a pathway — tiny, colorful dots starting in North Dakota passing through Minnesota, and moving down through Illinois.

I’m going to break it to you now and say that this is not a map of gumballs. It was produced by the investigative reporting nonprofit ProPublica, and because investigative reporting is rarely a cheerful enterprise, what the map actually describes are crude-by-rail accidents across the country. Still, let us be grateful, because it’s a Thanksgiving miracle we have this data at all.

As with a lot of miracles, the release of this information is the result of a lot of hard work. Early this summer, the federal Department of Transportation made an emergency order forcing railroads to share information on hazardous cross-country cargo with emergency responders in towns en route. The railroads countered this by pressuring states to sign non-disclosure agreements (NDAs) that would prevent anyone else from getting the information, at which point the Federal Railroad Administration stepped in and clarified that no one had to sign an NDA in order to get information. Since then, news organizations have been using public-records requests to access that information, and put it into a usable format.

ProPublica’s looks to be the most comprehensive map so far: It takes data on accidents compiled by the federal Pipeline and Hazardous Materials Safety Administration (PHMSA) and plots out where the train that had the accident was going and where its journey began. While the routes criss-cross the country, there are only a few destinations — since, as ProPublica puts it, “only a handful of places around the country have the refinery capacity and infrastructure necessary to handle the massive amounts of oil being extracted from North Dakota’s Bakken Shale: Bakersfield, Carson, and Long Beach in California; St. James, Lake Charles, Lacassine in coastal Louisiana; Philadelphia, Paulsboro, New Jersey. Delaware City, Delaware in the Mid-Atlantic.”

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After building the map, ProPublica called a few of the town along those routes and asked them what their emergency plans were for handling oil by rail accidents. This quickly got complicated, since many of the towns had no idea that trains carrying crude oil were passing through.

Along the journey south from North Dakota, for example, many trains now make a stop in the tiny town of El Dorado, Arkansas, population 18,500, bound for a refinery that recently added capacity to accommodate Bakken crude. The PHMSA hazmat data includes more than a dozen leaks found on trains headed for the town.

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Yet Union County Emergency Management Services deputy director Bobby Braswell, a former Chief Deputy for the El Dorado Fire Department, was unaware of the new crude traffic and its potential risks.

“We’ve got a little old railroad here, but if they transport crude, I don’t know,” said Braswell in an interview. If state emergency management officials have a plan to respond to oil train derailments, they haven’t shared it with El Dorado yet: “I don’t remember anybody calling about crude,” Braswell said.

In Philadelphia, which saw an oil train derailment a few miles out of downtown at the beginning of this year, the city still hasn’t developed a plan for dealing with an oil-by-rail disaster. ProPublica notes that the only emergency information specific to a fire involving crude oil, or any other hazardous substance, is video featuring “Wally Wise-Guy, the Shelter in Place Turtle.”

Wally may not be giving the best advice here.

One of the criticisms of the DOT-111 railcars that were converted from cars that carried corn syrup into cars that carried Bakken crude is that their hulls are so thin that if one of them catches fire and explodes, the cars around it can explode too, like a string of firecrackers. Some oil trains are a mile long. If one of those goes, a more realistic safety turtle might recommend being prepared to evacuate your city entirely.

That’s what happened in Casselton, N.D., last December, when 65 percent of the town’s residents evacuated the city after an oil train derailed and set off several explosions. Most fire departments only have the capacity to deal with a standard gasoline tank fire, about 9,000 gallons of fuel.  A single DOT-111 car holds about 30,000 gallons. So the local emergency crew did what they could do under the circumstances — which was to issue a recommendation to evacuate and let the fire burn itself out.

Oil-by-rail safety is complicated in the U.S. because railroads aren’t allowed to turn down any shipment, no matter how dangerous. Railroads like Burlington Northern Santa Fe (BNSF) make sure to mention this in their FAQ section:

Do you move hazardous materials in my community?

Railroads are required by federal law to move hazardous materials. Most of these include products used by consumers every day such as paint, batteries, alcohol-containing products such as hand sanitizer and insect repellent, and household cleaning products.

The hazardous materials of greatest concern to emergency officials are a tiny portion of all rail shipments, amounting to only about 0.3 percent of all rail shipments. BNSF helps train emergency responders across our system to ensure they are prepared to protect the public should such an emergency occur.

Railroads also don’t have a say in what kind of vessel those hazardous materials are shipped in. The containers are mostly leased from third parties, and regulating them is up to the Department of Transportation.

If only, given the incredible consolidation of wealth in this country, there were some kind of magical figure who had his own railroad, controlled over 40 percent of the leased cars, and was on record as having a philanthropic interest in public health. A person like this could make real change! And — actually — this person does exist:

[Warren] Buffett’s Berkshire Hathaway investment group is the biggest player in the tank car leasing business with around 40 percent of the market … The next biggest player, GATX Corp, is scarcely more than half the size. …

Buffett is also a major player in the railroad side of oil-by-rail. Berkshire Hathaway has full ownership of BNSF Railway Company, and BNSF is the biggest railroad player in the Bakken oil region … And BNSF isn’t some side line business for Berkshire Hathaway; it’s a major part of the firm, making up 13 percent of revenues in 2012.

Unfortunately, business and philanthropy do not seem to converge at the offices of Berkshire Hathaway.

It’s likely that if we have an oil-by-rail explosion equivalent to the Exxon Valdez spill, we’ll end up with something like what happened in the wake of that disaster — where oil by rail shipping doesn’t stop, but it gets more expensive, because shippers will have to pay into a common insurance liability pool. BNSF has proposed something different — federally funded liability insurance, not unlike the kind granted to the nuclear power industry in 1957.

All that is in the future, though. The more that we know about oil-by-rail, the better that cities in its path can prepare to deal with the risks that come with it.