RICHLAND, Wash. – Radioactive plutonium and americium have been found in air samples collected where workers enter the secure area of the Hanford nuclear reservation in southeastern Washington, state health officials said Tuesday.

The air samples were collected by the state Department of Health on June 8 at the Rattlesnake Barricade just off of public Highway 240, the Tri-City Herald reported.

That was the day workers at the Plutonium Finishing Plant were ordered to take cover indoors because of an airborne release of radioactive particles during demolition of the highly contaminated facility.

Department of Health officials at a Hanford Advisory Board committee meeting in Richland on Tuesday said analysis results for the air samples were received Monday.

The levels of contamination in the samples were “very, very low,” said John Martell, manager of the Radioactive Air Emissions Section of the Department of Health.

“The level is interesting from a regulatory point of view, but is not a health risk” to the public, said Mike Priddy, manager of the Environmental Sciences Section of the Department of Health.

Hanford employees were told in a Tuesday memo that the Department of Health considers “that the amount detected is below levels that would be of concern for human health.”

The Department of Energy and Department of Health are beginning an investigation and have not conclusively linked the airborne contamination to the Plutonium Finishing Plant incident, officials said.

“We are taking it seriously,” said Tom Teynor, Department of Energy project director for the Plutonium Finishing Plant.

The samples were collected in an area where officials were not expecting to find airborne contamination.

The Rattlesnake Barricade is at least three miles from the Plutonium Finishing Plant.