I think you mean a Safe-T-Alert Combination Carbon Monoxide and Gas Alarm. I agree with MKirkland, you should not smell any propane gas. There is a chance that the tank was over filled and you are smelling the blowoff.
Use a spray bottle filled with soapy water and see if you can find a joint that is leaking. Spray each joint and look for bubbles. If you can't find the leak, either take the RV to a place that installs propane tanks or a RV dealer with a propane sniffer. While you are waiting to get the RV in for service, turn off the propane at the tank.
IMHO, whatever you do, don't ignore it. Find the source and resolve the issue.
Paul