Environmental Concerns Prompted Commitments, Actions for Idaho Site Landfill

IDAHO FALLS, Idaho – Environmental monitoring near a waste repository originally named the “burial ground” at the Idaho National Laboratory (INL) Site officially began in 1960 when the U.S. Geological Survey (USGS) began drilling wells at the landfill perimeter to monitor for the migration of radioactive and hazardous constituents.

Of primary interest was protection of the Snake River Plain Aquifer, the second-largest continuous aquifer in the U.S., flowing 585 feet below the landfill. The aquifer flows through layers of basalt rocks at a rate of several inches to several feet a day in a south-westerly direction. More than 300,000 Idahoans rely on the aquifer for farming, drinking water and municipal water supplies.

In 1970, former President Richard Nixon signed the National Environmental Policy Act due to public concerns of air and water pollution. Elected officials from Idaho began to focus on waste disposal practices at the INL Site landfill. Federal agencies and a governor-appointed task force evaluated the risks and stated that the buried waste wouldn’t present a threat to the aquifer. Nonetheless, the Atomic Energy Commission, a precursor agency to DOE, committed to remove the buried transuranic waste there by the end of the decade.

Two flooding events occurred at the burial ground, the second of which happened in 1969. Site photographers took photographs of floating barrels and boxes of waste. The flooding took place during a rapid warming trend that melted nearby snow, resulting in the water flowing toward the lowest part of the landfill.

Soon after, workers built a diversion berm around the landfill to prevent future flooding. They also constructed diversion dams to channel the flow of the Big Lost River away from the burial ground, which was later named the Subsurface Disposal Area.

In 1971, engineers conducted tests to determine the condition of the waste and containers in the landfill and the soil migration of plutonium contaminants. They also assessed the ability to control the spread of contamination during waste retrieval, and the estimated costs for retrieval operations.

Later in the 1970s, workers removed more than 20,000 drums from portions of the landfill. They repackaged their contents in new drums and moved the drums to a nearby asphalt pad for above-ground disposal.

Crews continued to exhume buried waste in 1976, unearthing nearly 820 drums from the landfill. A few years later, engineers noted that drums and wooden boxes in the landfill had deteriorated to a point that workers could not retrieve additional containers.

By that time, the USGS was documenting the presence of trace amounts of radionuclides and higher concentrations of hazardous waste in wells adjacent to the burial ground. This prompted additional concerns by Idaho’s elected officials.