As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON CLIMBOUT, NOTICED A PLASTIC SMELL IN THE COCKPIT. SUPPLY PRESSURE INDICATORS SHOWED LEFT .31, RIGHT .38 PSI. RETURNED TO NORMAL PRESSURE AND SMELL DISSIPATED. FLIGHT RETURNED TO MSP AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED AIR PRESSURE REGULATOR.