I don't know the laws in Oregon, and my rig is too old for emissions, but If they want to be jerks I have been hassled about stupid things like where my tank is mounted, and illegal steel fittings. One clown said it is illigal in this state to have the tank mounted behind the seats, and said it had to be under the jeep. He wouldn't even fill the tank. Most people, are cool though. Some people will give you the discount becouse it runs on propane, others don't becouse the paper work is a hassle.