For more than a century, freight trains have rumbled up and over Montana’s Marias Pass, skirting the heavily forested south boundary of Glacier National Park, casting rolling shadows on the Middle Fork of the Flathead River below. Until recently the major threat was a grain car derailment, which on occasion left bears woozy from eating fermented grain and led to their deaths by train.

Today’s prospect of a derailment involving a 100-car train hauling millions of gallons of highly combustible Bakken crude oil risks an environmental catastrophe unprecedented in National Park Service history.

Every week an estimated 30-35 million gallons of Bakken crude oil passes along the park’s southern border as 10-12 BNSF Railway trains — with each tanker car holding about 30,000 gallons of crude — head from North Dakota to West Coast refineries and terminals. During the winter months, each mile-long train is exposed to a snowy Russian Roulette as they pass 11 avalanche chutes that could break loose without warning from mountains called Running Rabbit, Snowslip, and Shields on Glacier’s flanks.

Any day of the year, equipment failure, poor track conditions, or over-worked crews could lead to a derailment that could dump tens or hundreds of thousands of gallons of crude into the Middle Fork, a wild and scenic river, while an enormous fireball could ignite the park’s forests.

But Glacier National Park isn’t the only National Park System unit that faces this threat from “oil trains.” Fort Vancouver National Historic Site, in the state of Washington, could have four oil trains, each upwards of a mile-and-a-half long, hauling crude daily to a proposed but as yet unbuilt oil terminal at the Port of Vancouver.

National Park Service officials also point out that the Lewis and Clark National Historic Trail, the Oregon National Historic Trail, and the Ice Age Floods National Geologic Trail could be damaged by an oil train derailment. And, Fort Laramie National Historic Site, in eastern Wyoming, has an oil loading terminal less than a mile away that fills rail tanker cars destined for the East and West coasts 24 hours a day.

Park Service officials in Washington, D.C., were keeping an eye on the issue, and relying on their field staff to apprise them of any developments.

“We rely on National Park Service employees, like (Superintendent) Jeff Mow at Glacier who is engaged with communities near the park, to keep us informed on health and safety issues. Our concern is focused on visitor and employee safety, preservation of the cultural, historic and natural resources in our care and the health, safety and well being of our friends and neighbors who live near national parks,” said NPS spokesman Jeffrey Olson.

At individual parks across the National Park System, officials expressed great concern about the potential for a derailment in or near their parks.

At Fort Vancouver, Superintendent Tracy Fortmann said a derailment would “be catastrophic.”

“The threats are what you might expect,” Fort Laramie Superintendent Tom Baker said from his park in Wyoming. “If there were an oil spill, which most likely would be right at the crossing there just off of U.S 26 and Wyoming 160, that would be calamitous, to say the least.”

“We put together a map that shows the rail system that Bakken (crude oil) runs on nationwide, and we overlaid it with National Park System units. And we suddenly realized, holy mackerel, this is 48 states’ worth of a problem,” said Michael Jamison, who oversees the National Parks Conservation Association’s Crown of the Continent program. “The spills that are happening in (Lac-Mégantic) Quebec, on the James (River in Virginia), out in Casselton (North Dakota), they’re happening all over the nation. These are rails that run either adjacent to or sometimes literally through the center of a park.”

From Passengers To Oil

Railway history in the United States is richly intertwined with national park history. A century ago the Union Pacific Railroad, the Great Northern Railway, the Northern Pacific Railway, and the Santa Fe Railway and numerous short-lines filled their passenger cars with riders anxious to see America’s grandest natural attractions: Glacier, the Grand Canyon, and Yellowstone national parks, among others.

Gleaming locomotives — first steam-powered, and then by diesel electric — pulled coaches, replete with linen-topped tables and white-jacketed stewards in dining cars. Travelers bunked in Pullman sleeping cars, which provided a comfortable trip out West.

Scenic national parks gave the railroads strong promotional opportunities to sell tickets. The Union Pacific hauled passengers to Cedar City, Utah, where they boarded buses operated by the Utah Parks Co. (a Union Pacific subsidiary), to explore Zion, Bryce Canyon, and Grand Canyon national parks. The railroad was even hired by the Interior Department to build lodges within these parks.

But rail passengers eventually turned to automobiles, and the railroads’ focus turned to freight.

“In 1952, for example, only 22 percent of the occupants at Zion, 20 percent at Bryce, and 27 percent at Grand Canyon came by rail,” Maury Klein wrote in the second of his two-volume history of the Union Pacific. “In effect, the railroad was subsidizing the vacations of automobile travelers as part of its contribution to the Utah economy.”

Today, a growing portion of the railroads’ freight is crude oil, most from North Dakota. Day into night and into day mile-long trains rumble out of the state’s energy-rich northwestern corner, carrying millions of gallons of crude oil from the Bakken formation, which is fueling resurgence in U.S. energy independence.

But it’s at times a costly path. Oil train derailments have led to spills, and in some cases fiery explosions, in North Dakota, West Virginia, Illinois, and Virginia. On May 6, just five days after the U.S. Transportation Department announced more stringent regulations for oil train tank cars, a fiery derailment near Heimdal, North Dakota, sent billowing clouds of black smoke and billowing orange flames soaring into the morning sky.

“… the accident frequency trend is against rail. Oil trains are getting bigger and towing more and more tanker cars,” James Conca wrote in a piece for forbes.com on May 5. “From 1975 to 2012, trains were short and spills were rare and small, with about half of those years having no spills above a few gallons. Then came 2013, in which more crude oil was spilled in U.S. rail incidents than was spilled in the previous thirty-seven years.”

But do, or should, the railroads shoulder all the blame? As common carriers the railroads, which in most cases don’t own the oil tank cars they haul, are required to move a shipper’s hazardous materials, according to BNSF officials. For the railway, that means that their network of rails along the northern edge of the country has turned their trains into “rolling pipelines” from the Bakken boom to market.

“Other modes of transportation are able to turn down hazardous materials,” said Roxanne Butler, a BNSF spokeswoman. “Crude oil is a hazardous material and therefore, when a shipper asks us to move it, we are required to do so.”

BNSF isn’t the only rail company that hauls crude oil. The Union Pacific Railroad, CSX Transportation, and the Central New York do as well, and all their lines combined run like veins across the nation’s landscapes. Some of these oil trains, according to an NPCA analysis, pass alongside and, in some cases even through, parks such as Petrified Forest National Park in Arizona, New River Gorge National River in West Virginia, Mojave National Preserve in California, the Upper Delaware Scenic and Recreational River in New York and Pennsylvania, and the Mississippi National River and Recreation Area in Minnesota.

“In 2007, we ran about 6,000 tankers on the rail nationwide. A year later we had increased that by 50 percent, we were running 9,000 tankers,” says NPCA’s Jamison, who was drawn to studying the matter after Jeff Mow became superintendent of Glacier in August 2013 and asked about the tankers rolling over Marias Pass and down through John F. Stevens Canyon.

“Five years later, by 2013, we were up to 435,000 tankers. And we have gone from one ‘incident,’ as they call it, in 2007, to about 150-plus in 2013, nationwide. And so the numbers were pretty clear of what was going on,” he continued. “At the same time, of course, we had gone from approximately zero wells in the Bakken, to approximately 7,000. And my concern was that the whole build-out on the Bakken has been estimated not at 7,000 wells, where we’re at currently, but it’s 70,000-100,000 wells. And so you just do the math. From zero wells to 7,000 wells we went from 6,000 tankers to 435,000 tankers. So what happens when you add a zero, when you go from 7,000 wells to 70,000 wells?”

The Concern At Glacier

Glacier National Park rises in the “Crown of the Continent,” a rugged, mountainous landscape hugging the U.S.-Canadian border that is considered by some conservationists to be the United States’ largest intact ecosytem, a 10-million acre chunk of wild where, The Trust of Public Land says, “the list of plant and animal species living … has remained unchanged since the time of the Lewis and Clark expedition.” Rivers run swift, cold, and pristine, brimming with trout and cherished by river runners. Forests hold bears and wolves, elk and deer, wolverine and fox, while eagles and falcons wheel in the skies. Mountains here, the Great Northern reminded us, were, and still are, home to mountain goats.

Glacier National Park Superintendent Mow knows oil spills and their aftermath very well. He was on the NPS tort investigation team following the Exxon Valdez Oil Spill in Alaska in 1989, and 20 years later was superintendent at Kenai Fjords National Park while it was still dealing with some of the spill’s aftermath. More recently, Mow was an incident commander for the Interior Department during the Deepwater Horizon well blowout in the Gulf of Mexico in 2010.

Since taking the helm at Glacier, he’s met with BNSF officials to discuss their tracks that descend roughly 2,000 feet in elevation from Marias Pass down to West Glacier, a distance of about 46.5 miles.

The track corridor dates back to 1890. John Frank Stevens, then principal engineer of the Great Northern Railway, had crossed Marias Pass the year before with an Indian guide and determined it the best location for rail traffic. Today, two sets of tracks run along the southern boundary of Glacier, cross over the Middle Fork of the Flathead River before coursing along the boundary of the Flathead National Forest. The steepest grade, between the top of the pass and Essex on the western side, is 1.8 percent, according to BNSF.

BNSF recently conducted some maintenance work on Snowshed 5, but there are no plans to add sheds along the route, according to Ms. Butler.

Superintendent Mow is familiar with BNSF’s proactive efforts, which include sensors to monitor track conditions, to keep their trains on the tracks over Marias Pass and through the canyon. But, he adds, “We don’t operate trains and so quite honestly we don’t have the capacity to monitor their operations remotely.”

Since the tracks are outside the park’s boundaries, the Park Service has no official role in overseeing the train traffic and potential risks, the superintendent said.

“The only activity that we have issued permits for is avalanche mitigation during winter months,” said Superintendent Mow.

While an avalanche-caused derailment near the pass in January 2004 knocked 15 grain cars off the rails and closed the rail corridor for 29 hours, there have been no serious accidents in recent years. Yet the threat remains, and it’s a significant one when you consider the pristine river flowing below the tracks, the park’s forests above, and the explosiveness of Bakken crude.

“As we look at a response to a spill, there are just so many moving pieces that come into it,” the Glacier superintendent said. “From just whether it’s a winter vs. a summer spill, how you respond differently to that. It’s fascinating if you read about the (63,000-gallon oil) spill that occurred in the Yellowstone River this winter. There was that initial incident where the spill occurred, and how it impacted communities, then as the winter went on that calmed down, and as spring’s come along it’s remobilized a lot of the oil that was trapped in the snow and ice. It’s kind of a two-stage event, really.”

Recovering oil from rivers is not easy, cheap, or quickly done. Cleanup after a 2011 pipeline break at the Yellowstone River near Laurel, Montana, recovered only about 5 percent, according to NPCA’s Jamison. A major derailment in John Stevens Canyon could dump many tens or hundreds of thousands of gallons of oil into the Middle Fork of the Flathead.

“I think the chances of actually responding in a meaningful way, relative to the larger watershed and the aquatic ecology, are fairly slim,” he said.

John F. Stevens Canyon is narrow, often filled with wind, and in a remote, rugged location.

“Even out in Casselton, where you have room to operate, the answer in all these cases has been let it burn out. It takes three or four or five days, you let it burn out. Because it’s so hot they can’t get close to it,” the NPCA staffer said. “You add the complications of a very narrow, very windy, very rugged canyon, and there’s no way they’re going to fight that fire. It’s going to burn itself out.”

If such a fiery derailment occurred in August, during a hot, dry, windy “red flag” day with high fire danger, the problems magnify quickly, he said.

”We have people in the backcountry that we need to evacuate, and we have oil in the river and we have a couple thousand tourists, because that’s a white-water raft river…,” Jamison continued. “The first step (to preventing a disastrous spill) is you do everything you can to keep the oil in the trains, and I don’t think we’re doing that right now. We’re not even close to that right now.”

For their part, BNSF officials declined to say how prepared they were to handle a derailment in the canyon.

Getting Crude To Port

Fort Vancouver National Historic Site in Washington state was established in 1948 to preserve the setting for the western headquarters of the Hudson’s Bay Company on the Columbia River that dates to the early 1800s. In 1972 the city of Vancouver gave the park the Pearson Army Air Corps airfield, which dates back to the 1920s. Today the historic site blends story-telling of those two aspects within an urban park covering a bit more than 200 acres.

It also happens to have a BNSF rail line running along the southern edge of the park, sandwiched between Highway 14 and Columbia Way. The tracks already carry tanker cars, but the number could increase substantially if a proposal to build an oil terminal at the Port of Vancouver moves ahead.

“Stretching a mile or more in length, these 100-car trains pose a significant threat,” she said when discussing the potential of a derailment in her park, “It would be a horrific thing, it would be catastrophic.”

In its official comments on the terminal project, dubbed Tesoro-Savage, the National Park Service said that those proposing to build the facility and BNSF “should be required to develop robust mitigation and emergency response plans for the entire length of the supply and distribution lines.”

The NPS has called for extensive oversight, planning, and mitigation for the tracks that wind hundreds of miles back to the oilfields.

“These plans should consider both winter and summer conditions and should provide a rapid response in the event of a train derailment or marine oil spill,” the agency said in its official comments. “In areas of high snowfall, including at Glacier National Park, project proponents should investigate construction of snow sheds to prevent derailments and consider alternatives to using explosive devices to control avalanche events along the tracks.”

A decade ago, before oil trains were rolling, BNSF sought NPS permission to use explosives along the southern boundary of Glacier on a regular basis to control avalanches. The Park Service denied permission, and instead suggested that the railroad build more snow sheds. However, during the snowy winter of 2014 BNSF was given temporary permission to use aerial explosions, produced from a mix of hydrogen and oxygen, which creates a loud boom to trigger avalanches.

Now, with the daily traffic of oil trains coming through John F. Stevens Canyon, NPCA would like to see the railroad be more proactive in protecting its trains from avalanches.

“They need less than a mile of new shed. Not all in one place,” said Jamison. “In many places they’re just expanding the length of the shed that they have.”

BNSF’s Butler says multiple options are needed to keep trains running safely.

“Even with a robust avalanche risk minimization program that includes forecasting, snow sheds and operations restrictions, in times of high risk additional strategies may be needed,” she says.

Western parks don’t face all the dangers of oil trains. As the NPCA map shows and explains, rail lines wend their way, “along the Potomac and Shenandoah rivers and converge in Harpers Ferry, West Virginia. A derailment here could affect one of America’s most important historic sites and affect water quality for miles downstream.”

CSX tracks also travel through the gorge that cradles New River Gorge National River in West Virginia, and have been used to funnel oil trains to Virginia ports. However, the railroad has agreed to reroute oil trains around the New River Gorge National River.

CSX officials also have a mitigation plan in place that has led to quick response whenever there’s been a derailment in the gorge, the Park Service official said.

“Anything that goes into the river (soybeans, coal, corn, or oil) gets immediate reaction from their hazmat team, and their hazmat contractors,” Deputy Superintendent West said. “In my five years here, they have notified us within an hour of a derailment with a spill. We send rangers and resource management personnel to monitor the site – they work with us to solve the environmental concerns.”

The Danger Of Bakken Crude

Oil pulled from North Dakota’s Bakken Formation is particularly troublesome for shippers. Hal Cooper, a chemical engineer who has long studied the nation’s oil reserves and associated transportation systems, describes the crude “as being potentially hazardous in terms of flammability and volatility…”

One possible way to reduce that combustibility, he said, would be to remove the “volatile organic hydrocarbon vapors” from the Bakken crude before loading it into tankers.

When the ramp-up in production is considered, the problem becomes alarming.

“The state of North Dakota has undergone nothing less than an enormous increase in its crude oil production of less than 100,000 (42-gallon) barrels per day in 2006 to 300,000 barrels per day in 2010 and to 1,050,000 barrels per day at the beginning of 2014,” Dr. Cooper wrote in a report for the Puget Sound Regional Council.

Most of that oil, he points out, is carried by BNSF. In October 2013 it was estimated that the railroad hauled 620,000 barrels a day of the total 732,518 barrels a day produced in North Dakota.

The issue grows greater when you consider, as Dr. Cooper points out, that “there is a massive amount of crude oil lying underneath North Dakota in as many as 11 individual layers in at least five major formations. The total estimated oil resource in the Bakken Formation is between 300 and 500 billion barrels, of which between 4 and 6 billion barrels at a minimum to as much as 25 to 50 billion barrels at a maximum is considered as being presently recoverable.

“The total resource is as much as one trillion barrels of oil from all of the oilfields, in North Dakota, making it more than Saudi Arabia.”

Back at Glacier, Superintendent Mow says the volatility of Bakken crude “is a blessing and a curse, because being so volatile it’s been shown that fires are common with spills associated with the Bakken. But on the other hand, if it’s not burning it will evaporate on its own pretty quickly.”

Railroads try to be ready for the worst. BNSF and other railroads jointly run a first-responder training center in Pueblo, Colorado, to instruct them on how to attack tanker car fires. For its part, BNSF has a force of 160 trained emergency response personnel located across its rail network, and uses a system to “determine the most safe and secure routes for crude trains of 20 or more loaded cars.”

But BNSF officials would not say how close the nearest emergency response teams were to Glacier, Fort Vancouver, and Fort Laramie. They also declined to say whether the railroad has studied John F. Stevens Canyon to determine whether there’s a safer route for its oil trains; in July 2014 the railway had adopted Rail Risk-Based Traffic Routing Technology to “determine the most safe and secure routes for crude trains of 20 or more loaded cars.

While BNSF spent $5.4 billion on its rail operations in 2014, railway officials would not say how much was spent on track maintenance around those parks.

“Given the amount of work that it would require me to invest in your request, we are not inclined to participate in the story,” Ms. Butler said.

While the dangers of oil trains have been well-known for years, incidents seem to be increasing. On May 1, the U.S Department of Transportation along with its Canadian counterpart announced oil train regulations that would require stronger tanker cars, new braking standards, maximum speed limits between 40 mph and 50 mph, and routing analyses by railroads hat would review “27 safety and security factors.”

BNSF officials had a mixed reaction to the rules.

“BNSF has advocated for a safer tank car in the movement of crude oil and finally setting a new federal standard will get the next generation tank car into service and substantially reduce the risk of a release in the event of an incident,” the railway said in a statement.

“We have also said that any regulatory changes that automatically take away capacity will have a devastating impact on our shippers and the economy. Most importantly, capacity is not abundant. The supply chain’s experiences with the recent disruptions at the West Coast ports is clear evidence of the negative impacts substantially reduced capacity will have on the economy.”

At the American Association of Railroads, reaction from Edward R. Hamberger, president and CEO, was harsher.

“DOT has handed down an unprecedented railroad operating requirement that is 100 percent dependent on the actions of rail customers or tank cars owners,” Hamberger said. “This decision not only threatens the operational management of the U.S. rail system, but trains moving 30 mph will compromise network capacity by at least 30 percent. The far-reaching effects of this decision will be felt by freight and passenger customers alike. Slow-moving trains will back up the entire rail system.”

While the rules include a requirement that train speeds not exceed 40 mph in “high-threat urban areas,” Glacier and many other national park settings are not urban.

“The value of what’s at stake is so high — with regard to the wild and scenic river, the Flathead (Lake downstream), Glacier Park,” Jamison said.

In general, the resources that national parks preserve and protect demand the utmost safety precautions, he said.

“At Fort Vancouver, the human communities that are around it, the historic and cultural resources. What’s at stake is so high that we absolutely need to insure to the best that we can in case something bad should happen,” he said. “And that insurance means an investment in some site-specific infrastructure changes, and some site-specific rule changes in these places of high value.”

NPCA, said Jamison, believes speed limits also should be set for trains traveling through areas “of national significance with regard to natural and cultural values,” such as Glacier.

While speed can be a factor in derailments, so can faulty equipment. In the Casselton derailment — which dumped an estimated 400,000 gallons of oil when 21 of the oil train’s 106 tankers and two locomotives went off track — National Transportation Safety Board investigators focused on a broken axle on a grain car that derailed onto the tracks in front of the approaching oil train.

Despite new rules and precautions, with increasing oil train traffic, the odds of a serious derailment impacting a national park are more than likely only going to go up. Whether the response infrastructure is in place to prevent a major catastrophe is more difficult to answer.

“We don’t operate the railroad, but we just really want to emphasize what’s at stake in the event of an incident,” Glacier Superintendent Mow said. “So anything that we can do to influence safe operations and a spill never occurring, that’s one area for us to put some attention to. At the same time, we also have to be prepared for a spill, and to that extent our response capability, how would we interface with those first responders, the county and the state and the EPA as they ultimately become engaged.

“In this area, you call 911, and while 911 may direct you to Flathead County, Flathead County is often quick to call us because we’re the ones closest to being on the scene,” he added. “It becomes pretty integrated. We’ve had some early discussions, still need to do more tabletop exercises on some various scenarios to ensure that if there is an emergency we can have a smooth response, we don’t have to stand there and figure out who’s going to do what.”

How to improve safety, while not impeding commerce, is a question with few answers.

“We’re not out to stop transportation by any particular means. But the fact remains that these are literally bombs that run through our cities and next to our national parks,” said NIck Lund, NPCA’s landscape conservation program manager. “All it will take will be one more Lac-Mégantic. If a Lac-Mégantic accident happened in Philadelphia, where trains run constantly, or any of the cities that are involved here, that would sort of just completely change the nature of how this is thought of, I think.

“It’s a very difficult question I think a lot of people are struggling with what the answer is. Even if trains are the safest mode at this point, it only takes one incident for something really terrible to happen,” he said.