A watchdog group urged U.S. EPA today to require hardrock miners to post additional financial assurances in the wake of a new agency report on toxic pollution.

EPA's 2011 Toxics Release Inventory lists metals mining as the industry with the most releases of toxics, discharging 1.9 billion pounds of waste in 2011.

"In this sector, even a small change in the chemical composition of the ore being mined -- which EPA understands is one of the asserted reasons for the increase in total reported releases -- can lead to big changes in the amount of toxic chemicals reported nationally," the agency said in a news release.

Mining companies were largely responsible for the 19 percent increase in land waste released since 2010, EPA said. Surface water discharges declined 3 percent (Greenwire, Jan. 16).

Watchdog group Earthworks said the latest inventory shows a need for new financial assurance requirements for hardrock mines under the Superfund law. The agency is not planning to release a draft rule until next year, the group said.

"If the EPA doesn't act soon to require cleanup bonds, taxpayers could be paying the cleanup bill instead of the polluting mining companies," Earthworks spokesman Alan Septoff said. "Meanwhile, our nation's rivers, streams, air and land remain at risk."

The group's Northwest advocate, Bonnie Gestring, pointed to Hecla Mining Co.'s Lucky Friday silver mine as a prime example of a pollution source. EPA said it released 17 million pounds of waste in 2011.

"Idaho doesn't require a bond for underground mines, so taxpayers could be on the hook for more than $100 million in mine cleanup costs at this mine alone," she said.

Mining allies in Congress have criticized the impending new financial assurance requirements, even trying to insert riders into spending bills to control EPA action.

The lawmakers have pointed to Bureau of Land Management and Forest Service requirements for mines on federal land. The National Mining Association has also touted state laws and modern mining techniques (E&E Daily, March 9, 2011).

NMA has said that almost all substances reported in the toxics inventory occur naturally and that federal and state regulators already oversee disposal. The group has noted that the Toxics Release Inventory is not an evaluation of risk.

"Mining operations continue to represent a minor percentage of the total releases to air and surface waters covered in the TRI reports," NMA said in a statement, in contrast to land release numbers. "This has been a consistent feature of mining's reports over the 14 years mining operations have been included in TRI."

EPA said releases went up despite a fairly stable production output from mines. The National Mining Association, however, said there were increases in gold, copper, iron and molybdenum production. It also cited resumption of mining at a Nevada operation.

NMA and EPA both cited ore body composition and reporting requirements as a reason for the results. EPA said, "Such factors are particularly significant in cases where large quantities that qualify for a concentration-based exemption in one year may become reportable in their entirety the next year due to very small increases in the concentration of a toxic chemical in waste rock."

EPA received information from 87 metals mining facilities, mostly in the West. The agency said six of those had implemented activities to reduce their waste releases. It said companies recycled 49 million pounds and treated almost 13 million pounds of toxic waste.

Electric utilities and chemical companies ranked second and third on EPA's list based on TRI releases. The coal mining industry ranked 14th.