The Oregon cell phone law ORS 811.507 says that a “Mobile communication device means a text messaging device or a wireless, two-way communication device designed to receive and transmit voice or text communication."
A scanner does not meet the definition of a "mobile communication device" since it only receives voice communication and so it should be OK to listen to one while driving. I do and I've never been pulled over for it.
There is a subsection of the law that says it is illegal to listen to a mobile communications device with a function set to only receive one way voice communication. Since a scanner doesn't meet the definition of a mobile communications device, this section can't apply to a scanner.