Why work has stopped on a wall to keep ‘highly acidic’ waste away from the Great Salt Lake
US Magnesium was required to install a massive underground wall to keep “highly acidic” waste away from the lake, under agreements with the Environmental Protection Agency.
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- The US Magnesium dike north of Stansbury Island on Saturday, March 26, 2022.
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- This map, filed in federal court in Utah in 2021, shows the approximate outline of a retaining wall required at US Magnesium under the company’s settlement with the Environmental Protection Agency.
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US Magnesium acknowledges it has stopped working on a massive hydraulic retaining wall meant to protect the Great Salt Lake from its acidic wastewater — adding that it does not believe there are any current contamination leaks.
The mining company is being sued by the contractor it hired to build the retaining wall and six additional businesses, which each allege US Magnesium has not paid their bills for work, equipment or other resources in the past year.
Forgen LLC of Colorado stopped work on the wall in about November 2023, it said in its lawsuit, which contends US Magnesium owes it at least $5.8 million for five months of construction.
In May, the Environmental Protection Agency learned that progress on the wall had halted — and it informed US Magnesium that it was out of compliance with its 2021 settlement with the agency, according to public affairs specialist Katherine Jenkins.
US Magnesium is required to build the sunken retaining wall, clean up past contamination, add a new filtration plant to treat wastewater and make other improvements at its Tooele County plant under the agreement.
The settlement, called a consent decree, resolved US Magnesium’s past environmental violations, the EPA said, and set deadlines for the mandated work.
In an email to The Salt Lake Tribune on Wednesday, US Magnesium President Ron Thayer noted the company is no longer mining magnesium.
“In general, USM has ceased operations in the magnesium plant, and is no longer generating consent decree related wastes,” he wrote. “The work requirements specified in the consent decree involve modifications to magnesium related processing units that are not operational. As such, this work would have no benefit.”
The work related to the retaining wall “has been temporarily delayed due to the magnesium system shutdown,” he added. “In regard to environmental impact, US Magnesium has not detected any contaminant migration from our impoundment area,” referring to the waste pond region that will be surrounded by the wall.
The EPA and officials with the Utah Division of Environmental Quality, which is enforcing the consent decree, did not immediately comment Wednesday on Thayer’s assertions that the work is not needed and the status of contamination.
For now, the EPA is monitoring conditions around the Skull Valley plant to “ensure contamination is not exacerbated and impact to human health and the environment are minimized,” Jenkins said in an email sent earlier Wednesday to The Tribune. The agency has not assessed any new fines against the company, Jenkins said.
US Magnesium has long mined magnesium and other minerals from salts extracted from the Great Salt Lake at its plant 40 miles west of Salt Lake City. It is the sole producer of primary, or raw, magnesium, in the United States.
But the company stopped magnesium production in September 2022, it has said in court documents, and equipment failures the previous year had curtailed production even earlier.
Two weeks ago, US Magnesium announced it was also stopping lithium mining from its waste piles and laying off 186 workers, citing dropping lithium prices for the decision to idle its operations.
US Magnesium “does not have any immediate plans to restart magnesium operations,” Thayer said in his statement. “Should this change, all requirements related to the original consent decree will be executed.”
A series of suits
Forgen, a geotechnical engineering firm with offices in Centennial, Colorado, says it began construction on the “underground pollution mitigation wall” at US Magnesium in June 2023.
The plan reached by US Magnesium and the EPA calls for the retaining wall to stretch down to the level of a underground clay layer on the north, south and east sides of the plant’s waste pond areas.
By November 2023, work had halted because US Magnesium had not paid a single one of the company’s five invoices, Forgen alleges in its lawsuit, filed in October in 3rd District Court. The mine owes Forgen $5.8 million, plus interest and fees, according to the complaint.
Forgen and at least one of the other companies that sued US Magnesium between April and October said they have placed liens on its property.
Some lawsuits noted the equipment was for work related to the consent decree; others were less specific. All but one of the contracts were for work that began after the consent decree was issued.
US Magnesium has denied the allegations in the seven suits. It argues the mine did not damage rental equipment, as some contractors claim, or that the companies breached their contracts first, or that the claims have no merit for other reasons.
An eighth company, Odin Environmental Solutions in California, had settled a June 2021 suit against US Magnesium out of court. But it now is asking a Utah judge to enforce the remaining $1.5 million owed under that settlement.
US Magnesium acknowledged in a court filing Wednesday that it “has fallen behind on the payments” due to Odin “as a result of various factors [that] affect USM’s business and its inability [to] make EPA funds available.”
However, it added that “USM intends to continue trying to make such funds available and fulfill its obligations under the settlement agreement” with Odin.
Under the federal consent decree, the EPA set aside millions paid by US Magnesium under its 2018 bankruptcy settlement. Those funds can be made available, according to the decree, only after US Magnesium submits expense reports detailing work that has been completed at the site.
The decree also notes US Magnesium’s “inability to secure and/or maintain” the financial resources needed for the mitigation work “in no way excuse performance of the work or any other requirements of this consent decree or any other statutory or regulatory obligation.”
In his statement, Thayer said the company prefers not to comment on “discussions with regulatory agencies” as they are ongoing. It also “cannot provide comments on ongoing legal action related to other matters,” he said.
A hazardous history
Though US Magnesium typically has been a large source of toxic chemical releases in Tooele County, records show it hasn’t released chlorine, dioxins, hexachlorobenzene or other chemicals since it stopped magnesium production in 2022.
The operation has historically used a process called electrolysis to split salts from the Great Salt Lake into their atomic components, including sodium, potassium, magnesium and chlorine.
That produces a pure form of magnesium but also produces massive quantities of chlorine as a byproduct. In small quantities, chlorine is useful for the same reasons it is dangerous in large quantities: it can damage and even kill living cells.
The company’s past violations of the Resource Conservation and Recovery Act — the primary federal law governing the disposal of solid and hazardous waste — sparked the lawsuit that led to the consent degree and the designation of the US Magnesium facility as a Superfund site.
“Highly acidic” wastewaters were being “discharged into open air earthen ditches,” EPA inspector Annette Maxwell explained in a 2021 affidavit filed in support of the settlement. The company’s unlined waste pond covered 285 acres and was attached via an overflow pipe to an additional 800-acre unlined area, she said.
The settlement required US Magnesium to “construct an extensive barrier wall and berm,” Maxwell said, in order to comply with what is known as the nation’s Superfund law — the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA).
The wall would encompass approximately 1,700 acres of the site, she said, “to create an approximately 1,300-acre [retrofitted waste pond] to prevent leaks or breaches of hazardous materials to the Great Salt Lake.”
While there aren’t homes near the US Magnesium plant, wastewater from the company’s ponds has leaked into groundwater, according to a 2016 warning to US Magnesium from the Utah Department of Environmental Quality, and — like all water in the Great Salt Lake basin — made its way to the lake.
Soils, ponds and even the air around the plant contain large amounts of chlorine gas, hydrochloric acid and organochlorides like dioxins and a chemical called hexachlorobenzene, according to the EPA.
Hexachlorobenzene and other organochlorides can trigger cancer and tend to build up in the food chain. That could lead to chemicals from the plant getting into microorganisms and sediment around the lake where migratory birds root around for food.
The company did release about 5.3 million pounds of lithium carbonate — a chemical that can cause developmental and reproductive health issues — in 2023.
That’s 100% of the chemical waste US Magnesium managed last year. In previous years, the company has recycled or treated large portions of its waste.
Utah’s Division of Forestry, Fire and State Lands confirmed it hasn’t received a royalty payment from the company for magnesium alloy or pure magnesium since 2022.
Salt Lake Tribune Senior Managing Editor Sheila McCann contributed to this story.
