Covering Our Tracks

Sandia National Laboratories' Mixed Waste Landfill, a repository for varying degrees of radioactive and hazardous waste, has caused quite a stir over the years. Established during the Cold War in 1959 and closed in 1988, it serves as a graveyard for nuclear weapons research materials. With more than 40 types of radioactive elements buried beneath a mere 15-25 feet of dirt, there has been a great controversy within the last few years over what to do with the site.

Some parties have argued that the waste should be excavated and shipped to places more equipped to handle it; thereby eliminating any risk that it might bring to the city's water supply, citizens or ecosystem. Others worry that excavating the site could do more harm than good, by stirring up highly dangerous materials that have been sedentary for 17 years and potentially exposing them to people and the environment.

Now, it seems, the debate is drawing to a climax. In the wake of a recent ruling from New Mexico Environment Department (NMED) Secretary Ron Curry, approving a plan by Sandia to leave the waste and cap the site, a lawsuit has been filed against the state, claiming that such a decision is illegal. The outcome of the lawsuit could have far-reaching implications, helping to decide the level of responsibility that should preside over the site for generations to come.

What Lies Beneath

The Mixed Waste Landfill is one of Sandia's more than 100 waste sites; spanning over 2.6 acres, it includes an estimated 73 cubic yards of transuranic waste (which is about 200-250 55-gallon drums worth), including plutonium, tritium and cobalt-60. Not all of the contents of the site are known.

Technically, the landfill isn't a landfill at all, as it wasn't engineered to serve as one. Instead, the site is a series of unlined trenches and cylindrical holes between 15 and 25 feet deep, covering both classified and unclassified material.

The site sits directly over Albuquerque's aquifer, but to date has not leached any contaminates into the water. Ten years ago, tritium, a radioactive element that binds with water, was found to have traveled more than 100 feet into the earth, but was still considerably out of reach from the water table, which rests at approximately 460 feet below the surface.

Based off a “corrective measures” study completed in 2003, which studied the risks, cost and effectiveness of different methods to deal with the site, Sandia has come up with a plan to “cap” the landfill, allowing the waste to remain for the unforeseen future. Approved by NMED's Curry this spring, the plan entails covering the site with an additional three feet of dirt and implementing landscaping. NMED also requested that a bio-intrusion barrier (consisting of a one foot-thick layer of crushed, jagged rock) be put in place below the extra layer of dirt to help ward off burrowing animals.

Dick Fate, environmental restoration manager for project closure with Sandia, said the site will also remain closely monitored, and will be re-evaluated every five years to see if there are any signs that it should be excavated.

The cost of the project is estimated at more than $2.8 million, paid for at the federal level. If the site were to be excavated, Sandia estimates the cost would vary between $416 and $702 million. Continuing yearly maintenance of the site is estimated at $120,000.

Filing Suit

Citizen Action New Mexico, a local government watchdog group spawned from ex-members of Sandia's Citizen Advisory Board, has filed a lawsuit against NMED to appeal Curry's decision to approve Sandia's plan for the site.

Susan Dayton, director of Citizen Action, said the basis for the lawsuit is that federal law requires that transuranic waste be treated in a certain manner; specifically, it should be isolated in a location where it won't serve as a risk to humans for 10,000 years. She cites the Code of Federal Regulations, which states (in 40CFR191.13(a)):

“Disposal systems for spent nuclear fuel or high-level or transuranic radioactive waste shall be designed to provide a reasonable expectation, based upon performance assessments, that the cumulative releases of radionuclides to the accessible environment for 10,000 years after disposal from all significant processes and events …”

Dayton said only deep geologic repositories, such as the Waste Isolation Pilot Plant (WIPP), which is located more than 2,000 feet below ground, are acceptable for storing such high levels of radioactive waste, and certainly not shallow burials like the Mixed Waste Landfill, which is unequipped to handle such high-level waste in the long-term.

Adam Rankin, spokesperson for NMED, said Curry's decision was based on findings provided by Sandia that “there is no evidence or support for the contention that human health or the environment is endangered by the Mixed Waste Landfill. According to all reviews, air and water are protected and there is no indication these are in jeopardy.” Rankin also said that there is no requirement in the state's Hazardous Waste Act that transuranic waste be excavated.

Rankin added that NMED is requiring extensive monitoring of the site, and that if at any point it is shown that air and/or water are threatened, they will “take action to require mitigation.”

Dr. Eric Nuttall, one of several authors of a 2001 scientific peer review of the site and a professor in the Department of Chemical and Nuclear Engineering at the University of New Mexico, said he thinks NMED's decision seems prudent, at least for the time being. “I would concede that maybe that's the correct position at this point in time, but ultimately it should be excavated. Sandia says there is a very low risk of it hurting anyone; but this is not a passive set of materials. In fact, Sandia is saying they're so unsafe, we can't even dig them up.”

Still, Sandia's Fate said that, based on closely monitoring the site for at least 15 years and doing periodic testing of soil and water, the landfill shows a minimum risk of posing any threat to the city or environment. Fate believed there was so little risk, in fact, that he referred to the capping of the Mixed Waste Landfill as “an elegant solution.”

“We've been blessed. When they decided to create the landfill in the '60s, they knew the site was 500 feet above groundwater, and they were careful not to put liquids there—they kept it dry and covered—there's a small probability it will go anywhere,” said Fate.

Sandia has had problems with other landfills leaching waste into the groundwater, due to liquids that were tossed into the site. In the case of the Chemical Waste Landfill, which Sandia finished excavating mere weeks ago, TCE, a cancer-causing chemical, was found in the groundwater and had to be vapor-extracted out. If radioactive waste got into the aquifer, however, the water could never be completely restored.

Dayton used this as an argument to excavate the Mixed Waste Landfill. “This is old technology, they've done it before and done it safely; they can do it again.”

But Fate said the site is different from other sites, in that the landfill is not active enough to outweigh the risk of excavating it. He added that there are also some materials in the site (like radium 226, beryllium and cobalt 60) that, if brought to the surface, would be unable to be moved to another site, due to both their cumbersomeness as well as restrictions placed on other waste sites in terms of what they can accept. The cobalt 60 buried in the site, for instance, is encapsulated in two trucks of concrete, along with lead and steel, said Fate. “It's too big to move.”

But Nuttall said he thinks Sandia could move all of the waste if they put their minds to it. “Cobalt 60 is currently used and disposed of at Sandia, there are homes for that. It may not be in neat, tidy bundles with bows on them, but to say it's not possible to dispose of is not correct.”

Currently, Citizen Action is waiting for a court hearing to be scheduled. In the meantime, Nuttall aptly sums up the situation. “There are legitimate concerns here; we are dealing with legacy waste. This is not the best of times, but it's also not the worst of times. We're closing out the end of an era.”