Visitors to one of the world's greatest natural tourist attractions may have been exposed to higher than acceptable radiation levels for almost two decades.
Reports out of the US say uranium stored at the Grand Canyon National Park museum could have exposed visitors and workers to levels of radiation that are higher than the federal limit.
The park's safety manager Elston Stephenson told CNN he had raised the alert with officials last year but was ignored.
He said he had asked management at the National Park Service and Department of the Interior to warn workers and tourists that they had possibly been exposed to unsafe levels of radiation.
But when no action was taken, Mr Stephenson emailed all park staff at the Grand Canyon on February 4 this year.
"If you were in the Museum Collections Building (bldg 2C) between the year 2000 and June 18, 2018, you were 'exposed' to uranium by OSHA's (Occupational Safety and Health Administration) definition," he wrote.
"Please understand, this doesn't mean that you're somehow contaminated, or that you are going to have health issues. It merely means essentially that there was uranium on the site and you were in its presence. ... and by law we are supposed to tell you."
The National Park Service is now investigating what happened and is working with OSHA and the Arizona Department of Health Services.
But Mr Stephenson told CNN that in June last year he found out about three five-gallon (20-litre) buckets of uranium ore that had been stored next to a taxidermy exhibit at the park's museum for almost 20 years.
The Department of the Interior, which oversees the park service, issued this statement to CNN: "Uranium naturally occurs in the rocks of Grand Canyon National Park. 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. There is no current risk to the public or Park employees."
