FedEx Freight, the less-than-truckload unit of FedEx Corp., yesterday opened its first fueling center for vehicles powered by compressed natural gas, or CNG.

The facility, in Oklahoma City, will be used to fill 104 CNG power units that provide next-day service to all of Oklahoma and parts of Texas, Kansas, Missouri, and Arkansas, FedEx Freight said in a statement. The unit operates about 20,000 vehicles nationwide.

The center was designed and built by Clean Energy Fuels Corp., a Newport Beach, Calif.-based company. Clean Energy will also maintain the facility.

FedEx Freight will expand its CNG network if the Oklahoma City facility proves successful, according to a company spokeswoman.

The event was attended by Oklahoma Governor Mary Fallin; FedEx Chairman and CEO Frederick W. Smith; T. Boone Pickens, the legendary oil man and co-founder of Clean Energy, and Clean Energy President and CEO Andrew Littlefair.