A boat being hauled into Idaho from Nevada bypassed a state inspection station, was stopped by a Twin Falls County sheriff’s deputy and escorted back to the check station, and was found to be contaminated with live quagga or zebra mussels – the invasive mussels Idaho’s boat inspection program is specifically designed to keep out of the state and the region. The boat was impounded by the Idaho State Department of Agriculture, and will be released in the next 30 days only after “a thorough and complete decontamination.”

The contaminated boat had been purchased recently in Nevada, after being moored in Lake Mead; it was being hauled through Idaho on its way to Auburn, Wash. ISDA reports that since 2009, the state has inspected more than 300,000 watercraft and identified 145 that were carrying quagga or zebra mussels.

Montana, Wyoming, Washington, Oregon and Idaho are the only states in the West still free of invasive quagga and zebra mussels, which can cause massive damage to waterways, fisheries, irrigation facilities and more. You can read ISDA’s full announcement here; there’s more info here.