As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED AND THE AIRCRAFT RETURNED TO DFW DUE TO BURNING PLASTIC SMELL THROUGHOUT CABIN DURING CLIMB. THE AIRCRAFT LANDED SAFELY AT DFW. NO ODORS NOTED WITH APU OR ENGINE POWER RUNS. MAINTENANCE FOUND NO FAULTS.