As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB, CREW BEGAN DETECTING FUMES. THE ODOR INCREASED AT CRUISE FLIGHT AND WAS WORSE IN THE REAR CABIN AREA. FLIGHT WAS DIVERTED, WHEN THE FUMES INFILTRATED COCKPIT TO SUCH A DEGREE THAT THE FLIGHT CREW DONNED MASKS. MAINTENANCE REPLACED THE LT AIR CYCLE MACHINE.