The New Mexico Environment Department has demanded nearly a decade worth of records on nuclear waste handling from Los Alamos National Laboratory.

The new demand calls into question whether the lab has withheld information from environmental regulators investigating its role in a radiation leak last year, and whether a threat of another event lurks in more drums of waste packaged at Los Alamos that may have been mislabeled.

“NMED is unsure if DOE has been forthcoming with providing requested records/reports,” Jill Turner, a spokeswoman for the Environment Department, said Tuesday in an email. “However, as indicated in our requests, there are significant consequences for failing to respond truthfully. We expect that DOE will comply with the law.”

The order comes as state and federal investigators continue to examine the lab’s practices after a drum that originated there burst and caused a radiation leak at the Waste Isolation Pilot Plant near Carlsbad last year.

In a letter dated Feb. 17, the Environment Department set a deadline of March 9 for the lab to hand over its internal reviews of waste management practices and other records pertaining to waste handling between 2006 and the present or face fines of up to $10,000 a day. A senior LANL official said the lab plans to comply with the order and provide the records on time.

Federal reports released since the Valentine’s Day 2014 radiation leak at the Waste Isolation Pilot Plant, also known as WIPP, and internal lab documents obtained by The New Mexican under the federal Freedom of Information Act have raised questions about the way LANL handled and documented nuclear waste.

The drum that ruptured at WIPP contained highly acidic nitrate salts, an organic kitty litter absorbent and an acid neutralizer added at Los Alamos, outside the bounds of its permit issued by the state Environment Department. However, in its formal description of the package, LANL did not report the waste’s unusually high acidity nor the presence of neutralizer, and the description explicitly misstated that an inorganic clay variety of absorbent was used.

It references a set of documents submitted to the department by the lab last May that include an inventory of 707 drums thought to contain nitrate salts. Lab officials repeatedly have said the drum that ruptured at WIPP was unique in its volatility. But the Environment Department questions whether more troublesome waste might exist, but not be readily recognizable if LANL mislabeled it, like it had the drum that burst.

“NMED has reason to believe that certain internal reviews of waste handling practices have been recently completed, which indicate the total number of drums that may have been mislabeled is more significant than previously thought,” Turner said.

Missteps at LANL involving the drum that ruptured at WIPP were the basis for record-setting fines proposed against the lab’s permit by the Environment Department. In December, the department levied nearly $37 million in fines against the U.S. Department of Energy for LANL’s actions, and about $17 million in fines for WIPP’s error in accepting the waste in the drum that burst.

New Mexico Environment Secretary Ryan Flynn has threatened to impose about $100 million in new fines targeting LANL if negotiations with the Energy Department over the first round of fines are protracted. Hearings are scheduled for July 27 in the case of the WIPP fines and Sept. 21 for the LANL fines.

In its letter to LANL Director Charles McMillan demanding records, the Environment Department invoked a portion of the Hazardous Waste Act that requires permit-holding nuclear waste sites, such as the lab, to provide any information the department requests that would advance its investigations, rule making or regulatory enforcement actions.

“Your compliance with this information request is mandatory,” the letter states.

Contact Patrick Malone at 986-3017 or Follow him on Twitter @pmalonenm.