Source: Liz Kearney, Enterprise Staff Writer

The Gardiner Water and Sewer District has filed a lawsuit against the National Park Service over the amount of arsenic flowing into the District’s sewage treatment plant.
In the lawsuit, filed Dec. 21 in U.S. District Court in Billings, the Water and Sewer District alleges that wastewater coming from Mammoth Hot Springs is carrying such a large amount of naturally occurring arsenic that it will cost the district more than $2 million to remove arsenic-laden sludge from its sewage treatment ponds, per a requirement from the Montana Department of Environmental Quality.

The Gardiner Water and Sewer District has treated the sewage from Mammoth for many years, according to the complaint filed by the district’s attorney, Todd Shea, of Bozeman.
The district’s engineer believes the arsenic gets into the system through leaking pipes or manholes from within the park, “and that such conditions are likely prevalent along the route” from the park to the district’s sewage treatment plant, according to the complaint.

The complaint states that arsenic levels in drinking water in both Mammoth and Gardiner, as reported to the district by its engineer, test below the allowable limits.
The NPS needs to address the excess arsenic, the complaint states, because there’s no point in removing the sludge and replacing sewage ponds liners only to have more arsenic accumulate.

The complaint further states that the district wrote several letters to the NPS beginning in February of 2015 that went unanswered before the park agreed to contribute toward the sludge removal and lining replacement. But the park indicated it may not have any funds available until sometime in the year 2020, according to the complaint.

“Given that the District has been directed by the DEQ to dispose of the sludge and replace the liners in its treatment ponds and cannot wait for the Park Service’s responses any longer, it has been compelled to file suit,” the complaint states.

The complaint brings five charges against Yellowstone National Park:

• Breach of contract, for failing to follow through on addressing the high levels of arsenic and failing to contribute funds toward the repair process.
• Trespass. The complaint alleges the park is committing a “continuing trespass,” as the arsenic damage is ongoing and will continue until the park locates the areas of infiltration and repairs them.
• Public nuisance. The park “created a danger to public safety by permitting high levels of arsenic to flow into the District’s sewer treatment plant,” the complaint states.
• Private nuisance. The arsenic from the park forces the district to be responsible for removing and disposing of sludge with a high arsenic level.
• Negligence. The complaint alleges the park failed to monitor the condition of the pipes emptying sewage into the district’s plant, causing the district to suffer damages.

The Gardiner Water and Sewer District is asking the court to issue a mandatory injunction requiring the park to address and correct the high levels of arsenic; that the park contribute funds to the district’s sludge removal project “commensurate with their responsibility for the high levels of arsenic;” that the park pay financial damages and any other relief the court “deems to be just and proper;” and to pay attorneys’ fees and costs.

Representatives from the Water and Sewer District, Yellowstone National Park and the DEQ did not immediately return calls Monday seeking comment.