For nearly two decades, visitors to the Grand Canyon Museum Collection may have been unknowingly exposed to unsafe levels of radiation, according to a new report by the Arizona Republic. 

A “rogue” email sent on February 4 by the park’s safety, health, and wellness manager Elston Stephenson alleges nothing was done to warn visitors or workers of previous exposure to unsafe levels of radiation after three 5-gallon buckets containing uranium ore were found (and subsequently removed) by federal officials from the collections museum. In the email, the manager alleges the cover-up was a “top management failure”, further warning of possible health consequences from the radiation exposure.

"If you were in the Museum Collections Building (2C) between the year 2000 and June 18, 2018, you were 'exposed' to uranium by OSHA's definition," the newspaper reports the manager wrote. "The radiation readings, at first blush, exceeds (sic) the Nuclear Regulatory Commission's (NRC) safe limits. … Identifying who was exposed, and your exposure level, gets tricky and is our next important task."

IFLScience reached out to Stephenson but had not received a response at the time of publication. According to the initial report, he said buckets were stored in a room near a taxidermy exhibit frequented by tourists, including school-aged children. Radiation levels next to the uranium measured at 13.9 milliroentgen per hour – seven times the safe limit recommended by the NRC. While that same report also found the levels dropped to zero past 1.5 meters (5 feet), Stephenson alleges close proximity could have exposed adults to 140 times the health limit and children up to 1,400 times that.

However, it's unlikely that exposure to the buckets would have resulted in any serious health injury, reports The Verge, who talked with Kathryn Higley, head of Oregon State University's School of Nuclear Science and Engineering. Although she said "people should have been more mindful of them," she also noted that, based on the information she's read so far, “the likelihood of people receiving serious radiation exposures is extremely unlikely.”

Since the public wasn't hugging and lugging the buckets around for extended periods of time, the likelihood of anyone experiencing radiation sickness or its effects is fairly low, Higley noted. But why were they there to begin with? Well, she can only surmise, but she did say that the buckets were probably used as a teaching tool to show geologists what uranium ore looks like. Still, leaving the buckets behind – and for 18 years at that – is a sloppy mistake, nonetheless.  

In a phone interview with IFLScience, Emily Davis, public affairs specialist at the Grand Canyon, said that the Park Service is coordinating an investigation with federal experts, but that the area is currently safe to the public.  

“A recent survey of the Grand Canyon National Park’s collection facility found that radiation levels were at background, that’s the level that’s always in the environment and is below levels of public concern and safety,” said Davis, stressing that the museum collection facility is open to the public but available by request only.

All told, an estimated 800 to 1,000 visitors enter the 550-square-meter (6,000-square-foot) facility each year, which is used to hold and curate artifacts. When asked, Davis was unable to confirm whether these visitors may have been exposed to dangerous levels of radiation.

“It’s a research facility and we do store samples of many resources there,” she explained. “Samples in our museum collections facility [are stored] as part of our research collection as representative samples of park resources.”

Uranium ore is a naturally occurring element in the Earth’s crust and, when extracted from the rock that it is found in, can be used to make nuclear fuel. The area just outside of the Grand Canyon National Park boundaries is home to several uranium mines and hundreds of uranium claims. Exposure to large amounts of uranium can cause harm to the kidneys, and excessive exposure can cause cancer, including leukemia, according to the Centers for Disease Control and Prevention. 

IFLScience is awaiting a statement to be released by the NPS with new and relevant information. 

[H/T: Arizona Republic]