MEAD — The effort to determine the scope of AltEn Ethanol's effects on the surrounding area is not the first time residents of Saunders County have experienced environmental contamination on an industrial scale.
The Nebraska Ordnance Plant was named a national priority by the Environmental Protection Agency in the mid-1990s after an investigation found chemical solvents and explosives residue from the site had leached into groundwater.
While regulators and researchers explore how the pesticide-laden wet distiller's grains and wastewater stockpiled at AltEn continue to impact air quality as well as surface and groundwater, efforts to clean up environmental damage from the long-closed ordnance plant have already cost $140 million and could continue for decades.
Nebraska’s war effort
As the United States ramped up its war effort at home, thousands of construction workers descended upon the area in 1942 to build one of 27 bomb-making plants scattered throughout the country.
By August 1942, the plant’s 3,000 employees — nearly three-fourths of them women — began filling bombs with millions of pounds of explosives across four load lines, each situated a mile apart on the plant’s campus south of Mead.
Victory by the Allies in 1945 reduced the plant’s activity for several years until the U.S. entered the Korean War and gave it new life in the early 1950s.
The Nebraska Ordnance Plant was later placed on standby by the Army in 1956, and declared excess in 1959.
The University of Nebraska began leasing about half of the 17,000 acres of the former ordnance plant for an agricultural field laboratory beginning in 1962. Today, the site is UNL’s Eastern Nebraska Research and Extension Center.
As the ordnance plant was nearing the end of its life, the U.S. Air Force located an Atlas missile site near the northeast corner of the facility in 1958 as part of a growing effort to counter the nuclear threat from the Soviet Union.
More than 600 construction workers labored on the intercontinental ballistic missile site, which unlike later underground silos existed in an above-ground “coffin,” with the powerful Atlas missile needing to be raised and pumped full of liquid fuel before it could be launched.
Just as fast as the Atlas missile site was completed, the program was scrapped for the Minuteman system, which used solid fuel and could be launched quicker, leaving the government to abandon the above-ground launch site near Mead in 1964.
Chemicals leach into water
The U.S. Army Toxic and Hazardous Material Agency — charged with the decommissioning of military chemical and munition sites used in World War II and after — wouldn’t begin an investigation into the potential contamination at the former ordnance plant until the mid-1980s.
The government study only confirmed what was long suspected: The soil and groundwater in the area had been contaminated with chemical solvents and explosives residue.
In particular, the ordnance plant site had been poisoned by trichloroethylene, or TCE, used to clean metal pipes, and RDX, an explosives compound packed into bombs that would later be dropped on the Axis powers in combat theaters thousands of miles away.
At the end of each shift, workers at the plant would use high-pressure hoses to clean the concrete floors of the load lines, allowing TCE and RDX to leach into the groundwater over the next few decades.
When the Army Corps of Engineers began monitoring the site in 1987, mirroring similar investigations being done at the Naval Ammunition Depot in Hastings and the Cornhusker Ordnance Plant in Grand Island, it soon found the contaminants had spread underground in a slow-moving plume into area drinking wells south and east of the site.
By March 1989, the Corps planned to spend $2 million investigating the extent of the contamination, according to news reports at the time, while an official with the Office of the Army Secretariat estimated the cleanup could cost as much as $10 million.
But as more wells were dug, the situation grew more complex.
TCE was found in a well dug by the university northeast of the easternmost load line at the Nebraska Ordnance Plant at concentrations as much as 28 times the limit deemed safe by government regulators.
The location of the university well would have meant the chemical solvent had traveled upstream against the flow of the groundwater, engineers said at the time.
Or, as they would soon find out, a greater source of contamination was upstream from the plumes coming off the ordnance plant.
In the fall of 1989, the Corps determined the former Atlas missile site, where as much as 1,000 gallons of the chemical had been used each month to degrease and clean the pipes that carried liquid oxygen to the rocket was also leaching into the groundwater.
After a careful examination of the data, the Environmental Protection Agency determined the Nebraska Ordnance Plant qualified for the National Priorities List, which would put it well on its way to becoming a Superfund site.
Need to treat 100 billion gallons
Being eyed for the National Priorities List qualified the Nebraska Ordnance Plant immediately for more remedial investigations and risk assessments that were performed throughout the 1990s, said Bill Gresham, the remedial project manager for the site.
It also led more federal agencies to arrive in Saunders County, and eventually the funding spigot to be turned on.
Beginning in January 1990, and with the assistance of the U.S. Geological Survey, the Corps installed a ring of monitoring wells around the site to get a better idea of both the geology and hydrology of the site, or how the plume of contaminants may be traveling underground.
The Agency for Toxic Substances and Disease Registry, part of the U.S. Public Health Service based in Atlanta, arrived to study the contamination’s effects on the remaining employees of the ordnance plant, as well as the residents of nearby Mead.
The complex network of hundreds of monitoring wells gave the Corps a rough idea of the extent of the contamination by the mid-1990s.
Most of the TCE and RDX was contained in an area 4 miles long and 1½ miles across, stretching south and east from the Atlas missile silo along Clear Creek, with smaller plumes extending from each of the three other load lines.
In 1995, the Corps said containing and cleaning the contaminated plume would require treating 10 billion gallons of groundwater by pumping it through carbon filters.
Doing so, the engineers estimated, would require pumping upward of 40 billion gallons from the aquifer at an expense of $40 million, the cost to install extraction wells, lay pipe and build water treatment facilities.
The ongoing operational costs at the time were projected at $3 million per year, with the cleanup expected to take more than 100 years.
According to Gresham, at the end of the investigation, the EPA issued a record of decision for the ordnance plant in 1996, explaining the remediation plan for a Superfund site, and the agency immediately began to implement the plan.
Two extraction wells and treatment systems for the groundwater were installed in 1999, returning the treated water into outfalls in Wahoo Creek and Clear Creek.
A new, $15 million treatment plant opened in 2002 that could pump 4 million gallons of water per day through the system.
As the scope of the cleanup has expanded, so has the estimate for how much groundwater will ultimately need to be treated, however.
In 2002, the Corps of Engineers projected a total of 23 billion gallons of groundwater may have been contaminated since the 1940s.
To achieve that goal, more than 100 billion gallons of groundwater must be pumped through the system.
According to Gresham, the scale of the ongoing groundwater cleanup near Mead is consistent with other sites of similar size and scope, including at the two other munitions plants in Nebraska.
'A matter of what's practical'
Since the contamination from the Nebraska Ordnance Plant was first discovered, the Corps of Engineers, through the Formerly Used Defense Sites Program, has spent approximately $140 million on cleaning up the site, according to a spokesman.
A total of 430 monitoring wells, each checked by hand on a quarterly, annual or semi-annual basis, help the Corps track how the plume has changed or moved over time.
Controlling the contamination's spread are a system of 11 extraction wells, six wells outfitted with ultraviolet light capable of breaking down RDX, and three groundwater treatment plants that remove TCE.
In all, the system can pump 2,700 gallons of groundwater through treatment units every minute.
Gresham, of the EPA, which provides oversight of the Superfund site, said cleanup will continue for "several more decades."
“It’s not for lack of resources that the remedy isn’t going faster,” he said. “It’s really a matter of what’s practical, how much can we extract and treat.”
EPA and Corps officials say they are confident advances in technology could trim years, even decades, off the cleanup at the site.
For example, the water treatment plant opened in 2002 to pump groundwater through carbon filters has already been replaced by units that are less expensive to operate but just as effective in removing the chemical compounds.
Toby Hinz, a field operations manager for the Mead cleanup site, said the Corps regularly performs pilot studies looking for new, cheaper and more efficient ways of treating groundwater, and routinely implements new technology as it becomes available.
But, Hinz added, there's only one constant in cleaning up contamination that was allowed to spread unchecked for decades.
"It just takes time," he said.
PHOTOS FROM THE NEBRASKA ORDNANCE PLANT: