RICHLAND (AP) — The Washington state Department of Health says there is a possible risk to the public if demolition of the Hanford Plutonium Finishing Plant continues without better controls to prevent the spread of radioactive contamination.

The Tri-City Herald reported Wednesday that over the past year the Department of Health has requested information and made recommendations.

According to the Herald, Department of Health secretary Clark Halvorson expressed his concerns in a letter to the Department of Energy, warning that particles contaminated with plutonium or americium have spread outside the central Hanford area. None of the particles suggest an immediate risk to public health, however.

The particles were detected on vehicles driven off the site by Hanford workers.