For nearly two decades, visitors and employees at the Grand Canyon Museum may have been unwittingly exposed to high levels of radiation. According to a safety manager at the Grand Canyon, three paint buckets that were filled with uranium sat in a public area used for tours from 2000 to 2018.

“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,” Elston Stephenson, the park’s safety, health, and wellness manager wrote in an email to his colleagues.

He explained that visitors who spent about 30 minutes in the area could have been exposed to between 400 and 4,000 times the safe limit set by the Nuclear Regulatory Commission. The paint buckets were placed next to a taxidermy exhibit where kids would gather during tours of the museum. The children would have been exposed to unsafe levels of radiation within seconds.

Emily Davis, a public affairs specialist at the Grand Canyon, said that officials are working with the Occupational Safety and Health Administration and the Arizona Department of Health Services to investigate why the buckets of uranium were placed in a public area. She added that the buckets have been removed and the public is not in danger.