In the final days of Republican Gov. Susana Martinez’s administration, the state Environment Department approved a controversial change to how federal officials measure the amount of nuclear waste buried some 2,000 feet underground in Southern New Mexico salt beds.

Proponents of the change say it merely clarifies that the storage site will measure the actual volume of transuranic waste deposited there rather than the volume of the massive exterior waste drums, called overpack containers — and the air inside. But critics say the result will be an increase in the quantity of material stored at the U.S. Department of Energy’s Waste Isolation Pilot Plant near Carlsbad.

Several nuclear watchdog groups, which say they intend to appeal the decision, also fear the change in WIPP’s hazardous waste permit from the state could open the door to allowing high-level nuclear waste to be brought into New Mexico.

It’s unclear whether the Democratic administration of Gov. Michelle Lujan Grisham, who took office last week, will support the Environment Department’s decision in December or take any action to overturn it. The governor hasn’t yet appointed a Cabinet secretary to lead the Environment Department.

Tripp Stelnicki, a spokesman for Lujan Grisham, said the administration will be reviewing the potential impacts of the modification. But, Stelnicki said in an email, “that’s the case for all of the prior administration’s decisions.”

The governor “certainly recognizes safety at WIPP, for the public and for workers, is utterly paramount,” he added. “Safety is the expectation and that expectation will guide decision-making.”

Under the Land Withdrawal Act of 1992, Congress limited WIPP’s capacity to 6.2 million cubic feet, or just over 175,500 cubic meters. The plant, now about 52 percent full, is the only permanent repository for nuclear waste in the nation.

The 1992 law also limits the type of nuclear material that can be stored at the underground facility.

Under WIPP’s hazardous waste permit from the state, the volume of material stored at the plant has been measured based on the size of each exterior waste container.

Last year, however, the Department of Energy and Nuclear Waste Partnership LLC, a private company that operates the plant, told the New Mexico Environment Department the permit should be altered because it was forcing them to overcalculate the amount of waste at WIPP. Language in the permit required them to count empty space in large packing containers used to store smaller waste vessels — like hulking Russian nesting dolls.

“We don’t believe air should be counted as waste,” Robert Kehrman, a retired technical consultant for Nuclear Waste Partnership, testified during an October hearing on the issue. About 30 percent of what is now counted as nuclear waste at the plant “is something other than waste,” he said.

Plant managers and Energy Department officials said that without the permit change, WIPP would ultimately reach its full capacity too soon — with far less nuclear material than Congress intended.

Following a public comment period and a three-day hearing in Carlsbad in October, a hearing officer issued an opinion in favor of the permit change.

Butch Tongate, then the state’s environment secretary, adopted the hearing officer’s recommendation in late December, and the change is set to go into effect Jan. 20. WIPP will then be required to report both the total container volume and the interior waste volume.

Jennifer Hower, general counsel for the Environment Department, defended the decision in an email late last week, saying WIPP’s “limit is not changed by the permit modification.”

She also said the change does not affect the state agency’s authority over the nuclear waste storage site.

“The approved modifications to the permit do not lessen or relinquish NMED’s oversight of the facility,” Hower said, responding to critics’ concerns that the agency had ceded some power to the Department of Energy.

Any changes to the type of waste that could be held at the site would have to go through a separate permit and public hearing process, she added.

Still, critics believe the waste measurement change — after nearly 20 years of consistent measurement procedures — is a thinly veiled effort to expand the size and mission of WIPP.

“It was the wrong way to go,” said Steve Zappe, who testified at the Carlsbad hearing. Zappe spent 17 years working on WIPP for the state Environment Department and helped craft the plant’s original waste permit.

The permit modification, he said, was allowing the Department of Energy to redefine how much nuclear waste it can dispose of at WIPP without going through Congress.

Don Hancock, director of the nuclear waste safety program at the Southwest Research and Information Center in Albuquerque, estimated the change would expand WIPP’s capacity by more than 1 million cubic feet, or at least 30,000 cubic meters.

When WIPP began operations in 1999, it was only intended to accept transuranic waste — materials such as gloves and soil that have been contaminated with plutonium and other radioactive substances. The federal government was planning to open a separate repository for higher-level waste in Nevada. But development of the Yucca Mountain site stalled in 2010 amid opposition, and funding for the project ended the following year.

Without Yucca Mountain, the Department of Energy has considered placing 34 metric tons of weapons-grade plutonium at WIPP. While the plutonium would first be diluted through a complex process, Hancock and others have said it would still be a higher-level material than is allowed at WIPP.

Reports suggest the waste storage plant’s capacity isn’t large enough to even accommodate all of the transuranic waste planned for disposal there.

In 2017, the Government Accountability Office reported that WIPP does not have enough capacity for all of the transuranic waste kept at federal nuclear sites around the country, and to further expand the facility would require a lengthy regulatory process.

In November, the National Academies of Science, Engineering and Medicine published a report, requested by Congress, on the feasibility of disposing of excess plutonium at WIPP. It found that the plant’s capacity was one of the key barriers.

Hancock said he believes the Department of Energy has created a loophole through WIPP’s state waste permit that could allow disposal of weapons-grade plutonium in the future. He called the move “insidious.”

John Heaton, chairman of the nuclear task force for the mayor of Carlsbad, disagreed.

“The [measurement] process that has been used has been to count air,” he said. “And I think that is certainly not what Congress intended.”

James Mason, a spokesman for the U.S. Department of Energy’s Carlsbad Field Office, said the state permit modification increases efficiency at WIPP.

“We are making better use of [the space],” he said. “… It allows us to more effectively account for and utilize the space we do have.”

Reporter

Rebecca Moss has covered the environment and Los Alamos National Laboratory for the Santa Fe New Mexican since j2015. In 2018, she was selected to participate in the ProPublica Local Reporting Network.