The workers, employed by subcontractor Pueblo Electric, expressed concerns to their supervisor about black dust they encountered while replacing lights in two rooms within the building, located in Technical Area 08.

Subsequent testing of surfaces and equipment detected beryllium dust — which poses health hazards, even in small amounts — contaminating several rooms, including where the workers had been doing maintenance in late June, according to a U.S. Energy Department occupational incident report.

The rooms were either barricaded or had warning signs posted on them, the incident report said.

The workers were placed on a medical surveillance program. Lab officials on Wednesday declined to give their status, including whether they were still in the program.

“We cannot share health information about our workforce,” lab spokesman Steven Horak wrote in an email. “However, we can tell you that the health and safety of all of our workers is extremely important to us, and we take any risk of exposure to potentially dangerous materials, such as beryllium, very seriously.”

Horak wrote the building where the beryllium was found is being used, though he didn’t indicate what it was used for and whether employees regularly occupied it.

Because beryllium has been used extensively at the lab, all workers, whether employed by the lab or a contractor, receive at least fundamental training on the substance, Horak added.

Although a lightweight metal, beryllium’s strength and ability to withstand high temperatures makes it suitable for industrial uses and manufacturing.

The lab has used it to place a solid shell around the bowling ball-sized plutonium cores, or pits, that trigger nuclear warheads, and to test non-nuclear explosives.

When inhaled as a fine dust, it can embed in the lungs, scarring tissue and leading to chronic beryllium disease. Some common symptoms are shortness of breath, unexplained coughing, fatigue, weight loss, fever and night sweats, according to an Occupational Safety and Health Administration webpage.

Breathing in the toxin also increases the risk of lung cancer.

Beryllium has been at the lab since the 1940s, but larger-scale use began in Los Alamos in the early 1990s, after the Rocky Flats pit plant in Colorado closed.

In 2018, the Energy Department’s inspector general issued a scathing written report criticizing the lab’s beryllium oversight.

The lab failed to track the hazardous metal on several occasions, the report said, including with some misplaced contaminated equipment and a beryllium container lost at the time.

The lab also didn’t document its hazard assessments of the metal, resulting in employees not knowing the risks of working at sites where more than 50% of the beryllium inventory was kept, the report said.

The inspector general concluded the lab couldn’t ensure with confidence that exposure was within a safe limit.

The Energy Department’s Office of Enterprise Assessments followed up in 2019 with its own report, saying the lab had shown improvements in inventorying but that 20% of beryllium records still had inaccuracies or discrepancies.

The Energy Department’s report said the “frequency, location and minimum number of samples” was insufficient in work areas where beryllium was previously handled.

“If left uncorrected, findings could adversely affect the [Energy Department’s] mission, the environment, safety or health of workers and the public, or national security,” the report said.

Horak contends the lab’s workers are in no more danger than anyone else from this “naturally occurring metal that exists all around us, including in the dirt and dust that we walk on and breathe in daily.”

The Energy Department has limits for beryllium contaminating surfaces and the air in all of its sites, including the lab, Horak wrote.

“Outside of the DOE operations,” he added, “there are no national standards set for surface contamination levels.”

But an anti-nuclear activist argued it was misleading to characterize the lab’s beryllium contamination as “naturally occurring.”

“While LANL claims much of it is ‘naturally occurring,’ a great deal of beryllium was aerosolized during open-air explosive tests of mock pits, which for many years were a daily occurrence,” said Greg Mello, executive director of Los Alamos Study Group.

The widespread presence of this toxic substance at the lab is a longtime problem that will be all the more difficult to tackle because many of the lab’s managers are newly hired and lack institutional knowledge, Mello said.

Almost 24 years ago, the Energy Department began compensating weapons workers for exposure by setting up its chronic beryllium disease prevention program.

After that, records show the lab grappling with beryllium problems, according to a report by ProPublica and The New Mexican.

In 2006, safety inspectors discovered a large quantity of beryllium dust coating floors in a warehouse regularly used by workers.

Three years later, the lab informed nearly 1,900 lab workers and visitors that they possibly had been exposed to beryllium after it was found on several surfaces in a technical area.

In April 2015, beryllium hazards were listed among the problems that kept pit operations from resuming after they were shut down for three years due to a host of workplace safety violations.

Mello contends the latest incident shows beryllium is far from being a bygone hazard.

“This is bad, I would say, both in itself and in the frightening ease with which this occurred,” he said