Washington Examiner:

EPA and state officials say much of the toxic plume has dissipated in the Animas River, which the EPA confirmed Friday as being back to pre-spill conditions. But concerns remain that pollution in the rivers' sediment layers may have to be removed, with officials predicting a clean-up effort that could take years to complete.

The American Action Forum's study attempts to piece together estimates of the cost of the clean-up effort by reviewing a variety of the EPA's own assessments and modeling that were used for related events such as oil spills.

It also examined agency cost estimates for its controversial Waters of the U.S. rule, as well as regulations for limiting water discharges from power plants.

The study concludes that the cost of the toxic waste spill "might range between $2.7 million, $424 million, or $16.3 billion, but it will probably take months to assess the full damage," which could push estimates higher.

The study says using EPA's assessments for oil spills could push the clean-up costs to as high as $27.7 billion. But the study concedes that it cannot be precise in its cost estimates, because there is little precedent for the EPA to rely upon to inform a direct assessment of the clean up.

"I think it is more likely to be in the millions because the high-end figures are based off of oil spills in the Arctic (a close comparison), however the total volume for this is less than the average major oil spill," Sam Batkins, American Action Forum's regulatory affairs director, said in an email.

The study shows that EPA's cost assessment of a power plant rule is also instructive in determining the clean-up costs, because it deals with toxins being discharged into the water, although at much lower concentrations than were recorded in the Animas spill.

It says that the spill in Colorado released more than 3 million gallons of toxic sludge into the water, "which translates into more than 25 million pounds."

The group calculates that by assuming "a monetary equivalent of 90 cents per gallon of toxic waste the cost of the Animas River spill [will] be at least $2.7 million" when using the numbers from the power plant rule.