WASHINGTON — When a train derailed alongside the Mississippi River in southeastern Minnesota on Jan. 26, U.S. Rep. Tim Walz said it took 12 hours for the Federal Railroad Administration to announce the exact contents of six tanker cars that fell into the water.

It was not toxic chemicals, although a bit of flammable chemical leaked from another derailed car on the shoreline.

But for Walz, the accident proved why a new report criticizing the federal government's lack of planning and enforcement of rules regarding rail transport of hazardous materials needs immediate attention.

The audit report by the Department of Transportation inspector general resonates strongly in Minnesota where trains carrying crude oil, ethanol and other toxic substances crisscross the state each week. Many of those trains pass through heavily populated areas, where derailments threaten injury to hundreds of thousands of people as well as environmental devastation.

"It just does not feel to me like the sense of urgency is there," Walz said of the report, which strongly criticizes the Federal Railroad Administration (FRA).

The concern that accompanied a deadly oil train explosion in Canada in 2013 and subsequent oil-train derailments in North Dakota, West Virginia and Illinois has "ratcheted down," Walz said.

Six tanker cars fell into the Mississippi River in a January derailment, and it took hours to determine the contents of the cars.

Meanwhile, rail traffic in crude oil, which was just 9,500 carloads in 2008, reached 493,146 in 2014. Even as the shipments of the potentially explosive material skyrocketed, the inspector general said the FRA failed to refer any hazardous materials rule-breakers for criminal prosecution during the period the watchdog audited. Nor did the FRA levy significant fines on hazmat violators.

A spokesman at the FRA said its existing safety and enforcement efforts have already led to a decrease in accidents and a new record in 2015 for fines collected.

He said the agency is implementing many of the recommendations for better safety inspections made by the inspector general.

The watchdog group said a random national sample of inspection reports showed 17 cases that it believed should have been sent on to prosecutors, but were not. The sample also showed fines for safety violations were routinely so low that they "have little deterrent effect."

The report further blasted the FRA's lack of a national risk assessment of hazardous materials transport, especially not measuring how close train-shipped toxins come to people.

"The hazardous materials staffing process and National Inspection Plan do not take into account risk factors such as the condition of transportation infrastructure, the shippers' compliance histories, or the proximity of transportation routes to population centers," the inspector general noted.

A March 2015 study by the Minnesota Department of Transportation showed that 326,170 state residents live within a half-mile of rail routes that carry oil from North Dakota across Minnesota. A half-mile is the federal emergency response evacuation zone required in the event of a single tanker car spill and fire. Multiple-car fires require up to a mile evacuation.

The Star Tribune can find no record of the FRA ever forcing a railroad to reroute around heavily populated areas for safety reasons. Population is one of 27 measures the FRA considers when it judges whether hazardous materials train routes are safe.

Safety concerns just led state, local and federal officials and private interests, including BNSF Railway, to appropriate nearly $50 million to fund new track construction that reroutes oil trains around Willmar in southwest Minnesota. Each day, 14 to 17 oil trains from North Dakota rumble through the city of 19,600, all of them having to stop at a downtown track-switching station.

Members of Minnesota's congressional delegation, as well as Gov. Mark Dayton, have long called for increased vigilance in train safety.

The new inspector general's analysis shows that it has not occurred as it should have, they now say.

"As this report clearly shows, the Federal Railroad Administration needs to better identify and assess risks associated with the transportation of hazardous materials by rail," Sen. Amy Klobuchar said in a statement.

"It was not a good report," U.S. Rep Rick Nolan, told the Star Tribune. "In my [Eighth] district, we have 21 million gallons of oil a year coming over an old wooden railroad bridge from Canada. The report is a matter of great concern to me."

Nolan, a member of the rail subcommittee of the House Transportation Committee, said he intends to pursue the inspector general's finding and "bring in all the appropriate people, from the FRA to unions to the railroads."

In a written response to the inspector general, FRA administrator Sarah Feinberg cited a reduction in "non-accident releases of hazardous materials" and "renewed focus on enforcement to increase the consequences of violations."

A spokesman for the Association of American Railroads, a trade group representing major carriers, declined a Star Tribune request to comment directly on the inspector general's report. Instead, he focused on an improving safety record over recent decades.

As for enforcement efforts, he said in a statement that, "Anytime concerns are expressed by the FRA, they are taken very seriously by the entire freight rail industry and when the regulator releases an advisory or order, it is a priority for us."

Former FRA research and development director Steve Ditmeyer questioned whether stepped-up enforcement actions would make hazardous materials shipments safer. He said the risk that a single derailment can ruin an entire company drives compliance with rules.

"Moving hazardous materials is a you-bet-your-railroad proposition," Ditmeyer said.

Politicians answering to those who might be hurt in a derailment were less sanguine.

"With hundreds of thousands of residents living within a half-mile of tracks carrying oil trains, federal railroad regulators can't simply respond to serious safety violations by the railroads with a slap on the wrist," Sen. Al Franken said.

Walz, who said Minnesota dodged a bullet when the Mississippi River derailment released no toxic materials, still feels under the gun. The January accident in Houston County leaked 850 gallons of soybean oil into the water. Fifteen cars on a Canadian Pacific Railway train left the tracks with six going into the river. Walz said it should be a wake-up call.

"What's unacceptable to me about this is that there are things that happen when you have no knowledge that they are coming," he said. "This is something where we've been saying it's only a matter of time."

Jim Spencer • 202-383-6123