Several Shoshone-Bannock tribal members voiced concerns about how contamination from J.R. Simplot Co. and FMC phosphate processing operations on the Eastern Michaud Flats Superfund site could adversely impact the adjacent reservation where they live, grilling U.S. Environmental Protection Agency officials at a recent public information meeting at Fort Hall.
EPA officials gave updates about the Simplot, FMC, and off-plant “operable units” on the Superfund site, which covers 2,530 acres west of Pocatello, Idaho. FMC manufactured about 250 million pounds of elemental phosphorus annually within reservation boundaries until December 2001, when its plant was shut down. The Simplot phosphate fertilizer plant converts nearly two million tons of phosphate ore each year into five grades of solid fertilizer and four grades of liquid fertilizer east of the FMC site, but off the reservation.
An FMC pond that leaks phosphine gas and a large, unlined Simplot phosphogypsum stack behind its Don Plant that leaches into groundwater and discharges into the nearby Portneuf River and Batiste Springs generated the most heated questions from tribal members. Eastern Michaud Flats was listed as a Superfund site in August 1990 after investigations showed elevated levels of arsenic, lead, and cadmium above federal drinking water standards down gradient from the two plants, which were constructed in the latter 1940s.
In 1998, EPA signed a Record of Decision that identified cleanup methods. Primary contaminants of onsite groundwater are antimony, arsenic, fluoride, manganese, nitrate, radium-226, selenium, thallium, gross alpha, and gross beta. Offsite soils contain elevated levels of fluoride, radium-226, total phosphorus, zinc, arsenic, cadmium, and chromium. Onsite soils contain elevated levels of cadmium, chromium, copper, lead, nickel, silver, vanadium, zinc, radium-226, lead-210, total gamma radiation, and fluoride.
In 1994, the Portneuf River was listed as impaired for not meeting Idaho water quality standards for dissolved oxygen and nutrients, including orthophosphate. Its phosphorus level is above the Total Maximum Daily Loads (TMDL) of 75 micrograms per liter. The American Falls Reservoir downstream from the Portneuf is also impaired by low dissolved oxygen and algae blooms.
In April 2008, Simplot and the Idaho Department of Environmental Quality signed a compliance agreement in which Simplot agreed to reduce phosphorus discharges 50 percent by December 2013, 75 percent by December 2015, and 94 percent by December 2021 via source control, groundwater extraction, recycling, or treatment.
Simplot recently completed a field investigation to collect hydraulic properties of the aquifer and assess groundwater quality to fill in data gaps and help finalize how to remedy the contamination problem.
“Water is sacred to us Indians above all else. Any pollution to it is a bad thing,” Cleve Davis, a tribal member, said after Kira Lynch, EPA remedial project manager of Seattle, mentioned that EPA has reduced the maximum contaminant level for the Portneuf River.
Tribal council member Blaine Edmo questioned the wisdom of spraying contaminated water from about a dozen Simplot extraction wells onto the gypsum stack for dust suppression or expanding the stack that slopes toward the Fort Hall Reservation. If Pocatello or Chubbuck were directly north of the Simplot or FMC plants instead of Fort Hall, it would be a “different story,” he said. “Because the water flows back onto the reservation…nobody cares.”
A tribal woman criticized EPA for relying too much on studies by Simplot and FMC. “I can guarantee this isn’t something being done in a vacuum by the companies,” Lynch responded. Another woman asked, “How are you keeping FMC’s feet to the fire since the company is no longer operating there?” Lynch explained that FMC remains obligated to a cleanup because of a negotiated legal settlement. Elemental phosphorus has been detected as far as 85 feet below the surface to groundwater and extends 500 feet laterally on the FMC property, she said.
Eight capped FMC waste ponds range from three acres to 13 acres in size onsite and contain from 27 acre feet to 140 acre feet of waste. Their construction started in 1993; they were closed by 2006. In February 2006, high concentrations of toxic, flammable phosphine gas were detected escaping from Pond 16S. EPA ordered that a system be installed to capture and monitor the gas, which it declared was an imminent threat to human health and the environment. Pond 16S was the only FMC pond to have a complex mixture of wastes pumped into it, officials said.