Brandon Specktor reports that for nearly 20 years, a trio of 5-gallon (19 liters) paint buckets sat near the taxidermy exhibit at Grand Canyon National Park's museum collections building. Those buckets, it turns out, weren't holding paint — they were actually loaded with uranium ore, a naturally occurring rock containing uranium of unknown concentration that is slightly radioactive. Elston "Swede" Stephenson, a health and wellness manager at the park's South Rim, recently described the uranium find and subsequent minimization in a series of email blasts to Congress, his fellow National Park Service employees and the staff of The Arizona Republic newspaper.[ CNN even took up the story.]
Stephenson, [in language typical of those who pander fear to the public, claimed] that thousands of employees, tourists and school groups who visited the exhibit between 2000 and 2018 were likely "exposed" to dangerous amounts of radiation, especially groups of kids who sat for 30-minute presentations in the uranium's vicinity. These children may have been exposed to roughly 1,400 times the safe radiation dosage allowed by the Nuclear Regulatory Commission, Stephenson wrote. Scary stuff, if true, [but in detail it was a big to-do, about a minor issue, and Stephenson should be chastised for unnecessarily warning the public and damaging the reputation of the museum that would decrease the visits as a result of such unfounded fear mongering.] Several experts even told Live Science that Stephenson's assessment may be unfounded.
"If the time spent near the ore was short, there is likely little cause for concern," Bill Field, a professor of Occupational and Environmental Health at the University of Iowa, told Live Science in an email. For nearly 2 decades, Grand Canyon tourists were exposed to radiation beyond the federal limit, ... "Uranium ore stored at the Grand Canyon National Park museum may have exposed visitors and workers to elevated levels of radiation", according to the park's safety, health and wellness manager, [who apparently has not been educated regarding the potential impact of such radioactivity.]
Over time, uranium [can (does) break down into radioactive materials (called daughter products) like radium and release gas like radon. Studies of uranium miners (who smoked) have shown that prolonged exposure to uranium's decay products can increase the chances of getting cancer ]— However, Field said, "The risk from a few buckets of the uranium ore is quite different than a career in uranium mining." According to F. Ward Whicker, a radioecology expert and professor emeritus at Colorado State University, uranium ore chiefly emits gamma particles — the least dangerous type of radiation. "The amounts of radiation exposure from natural terrestrial sources and galactic cosmic rays to people living anywhere is far higher than most realize," Whicker told Live Science in an email. "Life flourishes in this constant radiation environment because DNA repair mechanisms operate efficiently and rapidly in cells — provided that intensity of radiation exposure is within certain levels."
The danger, if any, from the Grand Canyon ore buckets depends on a long list of factors, Whicker said, including an individual's distance from the ore, the length of their exposure, the quantity of ore in the buckets, the amount of uranium in that ore, and the amount of shielding provided by the rocky parts of the ore itself and the container.
In this case, the plastic paint buckets may have provided a powerful enough shield against the ore's radiation. Modi Wetzler, a chemistry professor at Clemson University who studies nuclear waste told The Arizona Republic that, while gamma rays can be dangerous if inhaled, they are easily absorbed and rendered harmless by just a few inches of air, or even a person's outer layer of dead skin. The ore's relative harmlessness is reflected in a report from the Parks Service, which Stephenson referenced in his emails.
After a teenager with a Geiger counter accidentally discovered the ore buckets in the museum in March 2018, the Parks Service launched a brief investigation to test radiation levels in and around the building. According to their report (which Stephenson quoted to The Arizona Republic), direct contact with the ore resulted in radiation levels at roughly twice the safe annual dosage allowed by the Nuclear Regulatory Commission — however, readings taken just 5 feet (1.5 meters) away from the bucket showed zero radiation.
The uranium ore has since been disposed of in a nearby uranium mine. Meanwhile, the Parks Service, the U.S. Occupational Safety and Health Administration and the Arizona Bureau of Radiation Control are now investigating the museum and its premises. According to Emily Davis, Grand Canyon National Park Public Affairs Officer, radiation levels at the site are normal and safe.
"A recent survey of the Grand Canyon National Park's museum collection facility found radiation levels at background levels — the amount always present in the environment — and below levels of concern for public health and safety," Davis told NPR. "There is no current risk to the public or park employees. The museum collection facility is open and work routines have continued as normal." Any long-term effects caused by the ore's 18-year stint in the museum remain to be identified, [signifying nothing of concern]. [While it might be negligible, the ore likely did increase the radon levels in the building somewhat, Field told Live Science, but air conditioning and heating would have certaining decreased any concentrations.]
In a final statement on the subject, "The facility should have been tested for any radon build-up," Field said. "Over the long term, however, the potential exposure from radon from natural sources in the soil and rock under the facility would likely be the greatest source of radiation to the public and workers."
Managed & Built by I2M Consulting, LLC | © 2010-
