Doug Bellfeuille / Minnesota Pollution Control Agency via Reuters

Crews work to recover an estimated 30,000 gallons of crude oil that leaked from three tanker cars involved in a derailment near Parkers Prairie in Minnesota on Wednesday.

A mile-long train hauling oil from Canada derailed, spilling 30,000 gallons of crude in western Minnesota on Wednesday, as debate rages over the environmental risks of transporting tar sands across the border.

The major spill, the first since the start of a boom in North American crude-by-rail transport three years ago, came when 14 cars on a 94-car Canadian Pacific train left the tracks about 150 miles northwest of Minneapolis near the town of Parkers Prairie, the Otter Tail Sheriff's Department said.

Canadian Pacific Railway Ltd, the country's second-largest railroad, said only one 26,000-gallon tank car had ruptured, adding it was a mixed freight train.

CP spokesman Ed Greenberg said he did not know if the crude was from Canada's tar sands or from conventional oil fields.

Minnesota Pollution Control Agency spokesman Dan Olson said up to three tank cars were ruptured and an estimated 20,000 to 30,000 gallons - or 475 to 715 barrels - leaked out.

Cold weather had made the crude thicker, hindering the ability to recover the oil, Olson said, adding the initial cleanup was expected to continue for a day or two.

"We are focusing on drawing up the loose (oil) ... and once that has been taken up, they will then pump up the remaining oil in the tanks," Olson said. "Because of the winter conditions, the ground is frozen and there is not any damage to surface water or ground water. After the initial recovery we will see if the oil has soaked into the soil at all."

In an updated statement, CP said just one car was compromised and other two cars leaked while being moved during the response to the derailment and were contained.

Greenburg said that the safe clean-up efforts were progressing well and without concern.

"There have been reports that clean-up has been challenging. Our crews are taking appropriate steps in ensuring clean-up is conducted appropriately."

A photo provided by the Minnesota Pollution Control Agency showed several large tank cars lying at the side of the railroad tracks in snow-covered fields, as clean-up crews examined the spill and maneuvered pump trucks into position.

"We have options to reroute traffic, so we've been able to continue to move trains while we do the thorough job of cleaning up the area," said Canadian Pacific's Greenberg.

A spokesman for the Federal Railroad Administration said two representatives of the U.S. rail regulator are investigating the incident.

There has been a rapid increase in rail transport of crude in the last three years as booming North American oil production has outgrown existing pipeline capacity.

Canada is the top exporter of crude to the United States, due to rising output of crude from its vast tar sands deposits.

Around 40,000 barrels per day on average were shipped to the United States in 2012, according to data from Canada's National Energy Board.

Suncor Energy Inc SU.TO, Canada's largest oil company, pulled the plug on its long-delayed and partially built Voyageur oil sands upgrading project in northern Alberta on Wednesday, citing surging volumes of crude from the Bakken.

'Good business for the rails and bad safety for the public'
Environmentalists have complained about the impact of developing the reserves, and have sought to block TransCanada Corp's controversial Keystone XL project, which would carry oil produced from the oil sands to the U.S. Gulf Coast refining center.

Some experts have argued oil-by-rail carries a higher risk of accidents and spills.

"It is good business for the rails and bad safety for the public," said Jim Hall, a transportation consultant and former chairman of the National Transportation Safety Board.

"Railroads travel through population centers. The safest form of transport for this type of product is a pipeline. This accident could - and ought to - raise the issue for discussion."

Others noted that spills from rail cars are rare, and crude-by-rail has opened up opportunities for companies to develop huge volumes of oil production in places like the Bakken shale fields in North Dakota, which are not well served by pipelines.

Total shipments of petroleum on U.S. railroads rose more than 46 percent last year to 540,000 carloads, the Association of American Railroads said in January.

"It's not very good publicity, but railroads are incredibly safe, they don't spill often," said Tony Hatch, independent transportation analyst with ABH Consulting in New York who has done work for major railroads. "It should not change the opportunity railroads have to make us more energy independent."

Supporters of the Keystone XL pipeline were quick to jump on the derailment as a reason to build the pipeline.

"It should be clear that we need to move more oil by pipeline rather than by rail or truck," said Don Canton, spokesman for North Dakota Senator John Hoeven, who has been one of the chief political proponents of the line. "This is why we need the Keystone XL. Pipelines are both safe and efficient."

Hoeven has supported the line as it would help carry oil produced in North Dakota to higher priced refining centers on the coast, and could help further expand production in the state that now pumps more oil than Alaska.

Melanie Thortis / Vicksburg Evening Post via AP

Barges wait for traffic to re-open along the Mississippi River near Vicksburg, Miss. on Monday.

VICKSBURG, Miss. -- With more than 50 vessels idled on the water for a fourth day Wednesday, authorities said they still did not know when they would be able to reopen a 16-mile stretch of the Mississippi River that was closed due to an oil spill.

A plan to pump oil from a leaking barge onto another barge — a process known as lightering — had been approved, but it was unclear how long that would take, Coast Guard Petty Officer 3rd Class Jonathan Lally said Tuesday. He said the other barge was en route.

Severe weather that was expected to sweep through the area could shut down cleanup operations for a time, prolonging the process further, authorities said.

Crews have been working around the clock to contain and remove oil since the barge, owned by Corpus Christi, Texas-based Third Coast Towing LLC, struck a railroad bridge and began leaking early Sunday. The company has refused to comment on the incident.

Lally also noted that about 7,000 gallons of crude oil were unaccounted for aboard the barge. He said it was not clear whether all of it spilled into the river or some seeped into empty spaces inside the barge.

At least 54 vessels, including towboats and barges, were idled on the river, one of the nation's vital commerce routes.

More than 168 million tons of cargo a year moves along the Mississippi between Baton Rouge, La., and the mouth of the Ohio River, carried by nearly 22,300 cargo ships and 162,700 barges, according to the Army Corps of Engineers. About 3.6 million tons of cargo is handled annually by the port of Vicksburg.

When low water threatened to close the river earlier in January, the tow industry trade group American Waterways Operators estimated that 7.2 million tons of commodities worth $2.8 billion might be sidelined over the last three weeks of the month.

Salt destined for Northern roads moves upriver in January, said spokeswoman Ann McCulloch. "We're still moving corn, soybeans and grain, but also coal and petroleum ... stone, sand and gravel," she said Tuesday.

Barges carry 20 percent of the nation's coal and more than 60 percent of its grain exports, according to the group.

Ron Zornes, director of corporate operations for Canal Barge Co. of New Orleans, said each idled towboat could cost a company anywhere from $10,000 to $100,000 a day. The low end would be for a single boat with a couple of barges and the high end for one in "a system of towboats that acts sort of like a bus system."

"So if one bus is stopped it gums up the whole system," he said. 

Andrew Burton / Reuters

Derailed freight train cars leak vinyl chloride, a colorless, organic gas with a sweet odor sit semi-submerged in the waters of Mantua Creek after a train crash, in Paulsboro, N.J., Nov. 30.

Residents were asked to stay inside their homes for hours after emergency and hazmat crews responded to a train derailment and hazardous material spill Friday morning in Gloucester County, N.J. More than two dozen people have been transported to a local hospital with respiratory problems after the incident.

Gloucester Office of Emergency Management confirmed that a Conrail train derailed after the bridge it was traveling on collapsed -- for the second time in a little more than three years -- just after 7 a.m. Friday near Commerce Street in Paulsboro, Gloucester County.

Six of the train's cars were dumped into Mantua Creek. Four of the cars contained vinyl chloride, a colorless, organic gas with a sweet odor. One of the train cars was compromised, releasing about 180,000 pounds of the chemical into the creek, according to Conrail spokesperson John Enright.

For more, visit NBC10.com

Vinyl chloride is a colorless flammable gas that is used primarily to make polyvinyl chloride (PVC) pipes. It's heavier than air and can travel along the ground, but it evaporates quickly.

Acute exposure via inhalation in humans can cause dizziness, drowsiness, headaches, and even a loss of consciousness, and it is reported to be slightly irritating to the eyes and respiratory tract, according to a statement from Gloucester County Freeholder Director Robert Damminger. Anyone who thinks they're suffering any symptoms due to exposure is encouraged to seek medical advice.

"The company [Conrail] will offer assistance to residents who sought medical attention," Conrail spokesperson John Enright said. 

Residents were initially told to remain in their homes and local schools were placed on lockdown as emergency officials assessed air quality concerns. At least 28 people were transported from the scene to Underwood Memorial Hospital, all complaining of respiratory problems. Officials confirm that some of the injured are workers from the Paulsboro Marine Terminal. 

“Personal safety is our number one concern,” U.S. Coast Guard Petty officer Nick Ameen told NBC10.

Officials determined at about 11 a.m. that air quality had improved, meaning the situation was under control. However, they cautioned that the next significant threat will be when Conrail attempts to lift the cars out of the water without releasing any more chemicals.

Photos: Paulsboro Train Derailment

Paulsboro School District was on lockdown until 11 a.m. Students were dismissed when officials determined the air quality had improved.

The School District's Superintendent Dr. Frank Scambia told NBC10 that 50 students from all three of the district's schools were on lockdown inside the gymnasium at the high school.

The Fire Department also evacuated all employees on Commerce Street.

"The whole day is a wash," Doug Ricotta, owner of D&D Italian Bakery, told NBC10. "Everything's shutdown."

Roadways leading into Paulsboro were closed.

Officials say the biggest concern right now is the time when the cars are lifted out of the water, although they've already devised a plan to contain the vapors.

"Right now, the remaining chemical is frozen, at the bottom of the car," a Paulsboro official said. "[but} The Conrail engineers and hazmat crews are experts at plugging holes and sealing things and I'm sure they'll do what they need to do to stabilize that product."

The cars, however, will not be lifted out of the water until at least Saturday because it will take a day to bring in a crane large enough to lift the cars.