The lab informed the U.S. Environmental Protection Agency earlier this month that it would ventilate four waste containers, beginning April 17, to relieve the built-up, radioactive hydrogen in the barrels’ headspace to prevent them from rupturing while they’re being handled. The EPA approved the application for the radioactive release last year.

Lab personnel will ventilate one container at a time and filter the released vapors through on-site equipment to limit the amount of tritium that is discharged into the atmosphere, according to the lab’s EPA application.

Tritium is a radioactive hydrogen isotope and is found, both naturally and human-made, in water, soil and the atmosphere. It is generally only harmful when ingested in high doses in food and water, and can increase the risk of cancer in some people, according to a Health Physics Society webpage.

However, some medical researchers contend any amount of radiation exposure can risk damaging tissues, cells and DNA, potentially causing genetic mutations, birth defects and cancer.

Because radionuclides — such as those found in tritium — are carcinogenic, the EPA has stated the goal should be zero emissions, though the agency allows some discharge, said Charles de Saillain, an attorney with the New Mexico Environmental Law Center.

“There is no safe level for radionuclides,” de Saillan said. “The more radionuclides you put in the atmosphere, the worse it is.”

The tritium in the four waste drums adds up to roughly 114,000 curies of radiation. A curie is a unit of radioactivity equal to what a gram of radium emits.

The lab’s application states high-efficiency particulate air filters and other equipment would significantly reduce the tritium if it is released, though it couldn’t say by how much.

“We have emissions controls to capture some of the tritium, and active monitoring in place to ensure that we protect public health and safety and do not exceed regulatory limits,” said Toni Chiri, a spokeswoman for the National Nuclear Security Administration, a semi-autonomous branch of the Department of Energy.

One anti-nuclear advocate said he didn’t trust the agency’s statements on how it will reduce the amount of tritium that’s released.

Jay Coghlan, executive director of Nuclear Watch New Mexico, said in the 1990s he won a lawsuit against the Energy Department for falsely claiming a building’s “shielding factor” kept radioactive emissions within federal limits.

“The undocumented assertion in the application that half of the tritium could remain behind in equipment should be viewed with suspicion,” Coghlan said.

The lab aims to keep the released tritium radiation to 8 millirems, staying within the 10 millirems that federal guidelines permit the lab per year, according to the application.

A millirem measures radiation exposure.

“I don’t see from the document any radiation overexposure concerns for the general public,” said Bemnet Alemayehu, a radiation health scientist at the Natural Resources Defense Council. “However, the release should be controlled and monitored to avoid any uncontrolled release risks.”

One or two drums would be ventilated per week and shipped to a commercial waste storage site.

Wind velocity and direction would be factors during the release, which could lead to less tritium being discharged.

If the federal limit is reached before all the drums are ventilated, the remaining drums would be put back into storage at the lab until next year.

This tritium is a byproduct of nuclear weapons production during the Cold War.

The lab has become more cautious about containers being combustible after a crew packed a waste drum with a mixture of wheat-based cat litter and nitrate salts in 2014, causing it later to explode and leak radiation at the Waste Isolation Pilot Plant in Carlsbad.

WIPP shut down for three years and the cleanup cost was about $2 billion.