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Release Date: 10/19/2000
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Attached is EPA’s Region 9 press release announcing a settlement up to $1 billion with Aventis CropSciences USA, Inc., to resolve future cleanup costs at its Iron Mountain Mine Superfund site in California.
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Agreement will clean up one of country’s most toxic Superfund sites

SAN FRANCISCO – The United States and the state of California today announced a settlement with Aventis CropSciences USA, Inc. that will fund future cleanup costs that could approach $1 billion at the Iron Mountain Mine Superfund Site nine miles northwest of Redding, Calif.

The settlement, on behalf of the U.S. EPA, the U.S. Department of the Interior, the U.S. Department of Commerce and several state agencies, is one of the largest settlements with a single private party in the history of the federal Superfund program. It is also one of the biggest environmental settlements for state environmental agencies.

The settlement will ensure long-term control of more than 95 percent of the releases from Iron Mountain, historically the largest point source of toxic metals in the country, and the source of the most acidic mine drainage in the world. Prior to remediation, the mine discharged an average of a ton a day of toxic metals into the Upper Sacramento River, a critical salmon spawning habitat and a central feature in the state’s water system.

Aventis, formerly known as Rhone Poulenc, Inc., has arranged for The IT Group to operate and maintain the site cleanup over the next 30 years, and for a payment to the federal and state governments of $514 million in 2030 to pay for future site costs. This unique funding mechanism enables Aventis – who is securing the funding through a financial assurance and insurance vehicle specifically tailored for this settlement – to pay roughly $160 million to fund the long-term operation and maintenance at the site (an estimated cost of $200 to $300 million), a payment to the U.S. EPA of approximately $8 million and a payment to the natural resource trustees to fund natural resource restoration projects ($10 million). The settlement also waives $150 million in past costs, bringing the total amount to close to $1 billion.

“This innovative settlement is good news for people, fish and animals from the northern headwaters of the Sacramento River all the way down to San Francisco Bay,” said U.S. EPA Regional Administrator Felicia Marcus. “As recently as five years ago, this site dumped the equivalent of 150 tanker cars full of toxic metals into the Sacramento River each day during winter storms. Now, thanks to a true team effort on the part of myriad federal and state agencies, we have the funding and the resources in place to dramatically curtail the damage this site has imposed on our natural resources.”

"This agreement is an excellent example of government and the private sector working together to develop a solution to a serious environmental problem," said Winston Hickox, Secretary of the California Environmental Protection Agency. "The environment and California taxpayers will both benefit – the Sacramento River will be less polluted and taxpayers will not have to foot the bill."

“Controlling toxic releases from this massive hazardous waste site will allow salmon to once again migrate and spawn in the Sacramento River. Protecting and restoring chinook and steelhead salmon is an important priority for NOAA, and we are pleased to have worked with EPA to find a solution that restores habitat for these important fish species, " said Craig O'Connor, Acting General Counsel for NOAA.

The Settlement

Some key elements of the settlement include:

The settlement guarantees long-term funding through an insurance instrument with the highest-rating available, AAA;

The IT Group will operate and maintain the Iron Mountain remedy as the site operator over the next 30 years;

The natural resource trustees will receive $11 million to pay for natural resource restoration projects;

The government will receive a payment of approximately $514 million in 2030 to fund site costs after year 30.

The Site History

From the late nineteenth century through 1963, the Mountain Copper Company, Ltd. mined the site for various minerals – including iron, gold, silver, copper, zinc, and pyrite – both underground using open stope mining techniques and at the surface in the form of open pit and sidehill mining. The mining operations fractured the mountain, changing the hydrology and exposing the mineral deposit to oxygen, water and certain bacteria, which has resulted in intensely acidic mine drainage into nearby creeks and waterways.

“The discharge from Iron Mountain is so toxic that when workers inadvertently left a shovel in the green liquid flowing from one of its portals, the next day half the shovel had been eaten away completely. You can imagine what damage this type of drainage could wreak on the local ecosystem,” Marcus said. “ Prior to government cleanup actions, large storms frequently wiped out salmon and steelhead downstream of the Iron Mountain discharges. Now, thanks to the treatment plant, massive fish kills are a thing of the past.”

In addition to its low pH, acid mine drainage from the site contains extremely high levels of copper, zinc, cadmium and other metals. Prior to the action required by the U.S. EPA and the state, the mountain discharged approxi-mately a ton of copper and zinc each day – equal to approximately one quarter of the total national discharge of copper and zinc to surface waters from industrial and municipal point sources.

High pollution levels associated with mining at the site have been known for decades. Since the turn of the century, the state and federal governments have documented the problems with the site’s acid mine drainage, primarily its impacts to the Sacramento River and to the upstream tributaries flowing down the mountain. In 1963, the federal government constructed the Spring Creek Debris Dam in large part to meter the polluted flows from Iron Mountain into the Sacramento River, rather than allowing those flows to enter the river in an uncontrolled manner.

The EPA listed Iron Mountain Mine as a federal Superfund site in 1983, at the request of the state of California. The heart of the U.S. EPA’s and the state’s strategy to deal with acid mine drainage involved building a high density sludge treatment plant in 1994 that removes 99.99 percent of metals from the site’s toxic runoff. Since 1994, the treatment plant has removed more than 5 million pounds of heavy metals, including copper, cadmium and zinc, that would have otherwise been discharged into the Sacramento River. By comparison, the entire city of Sacramento discharged approximately 100,000 pounds of metals during that same period.

Numerous state and federal agencies have worked together on this site, including: the U.S. EPA; the National Oceanic and Atmospheric Administration; the U.S. Bureau of Land Management; the U.S. Department of Justice; the U.S. Bureau of Reclamation; the U.S. Fish and Wildlife Service; the National Marine Fisheries Service; the California Environmental Protection Agency; the Department of Toxic Substances Control; the Central Valley Water Quality Control Board; the California Department of Fish and Game; the State Lands Commission; and the California Resources Agency.

What’s Next
In addition to continuing to control runoff, the U.S. EPA working with the State of California will perform several activities in the coming years, the first of which will be constructing a dam on Slickrock Creek that will collect additional acid mine drainage and send it to the site’s wastewater treatment plant. This action, when combined with the current remedy, will control more than 95 percent of total site releases. Other plans include conducting further study and potential cleanup of the sediment in the Spring Creek arm of the Keswick Reservoir and acid mine drainage sources in the Boulder Creek watershed.

Additional information on Iron Mountain Mine is available on the Web at


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