ONQUEST WINS DESIGN PROJECT FOR
TESORO MANDAN DDU EXPANSION

To Design New Reactor Charge Heater for Refinery Upgrade

Los Angeles, CA (September 25, 2012) - San Dimas, Calif.-based OnQuest, Inc. has won a project to provide engineering design and procurement for the reactor charge heater to be used in the $35 million expansion of the diesel desulfurization unit (DDU) at the Tesoro Mandan Refinery in Mandan, North Dakota.

OnQuest will supply engineering and procurement for the vertical cylindrical reactor charge heater, to be rated for 20 million Btu/hr. OnQuest will also oversee final assembly and modularization.

"Tesoro is a long-time client for a range of design and engineering services," said Randy R. Kessler, OnQuest's president and CEO. "It is extremely gratifying to again win a competitively bid project based on OnQuest's technical expertise and proven ability to deliver."

Tesoro's upgrade of the DDU is planned to increase capacity of the diesel processing unit to 22,000 barrels per day from 17,000. The project is scheduled for completion in Q4 2013.

Established in 2002, OnQuest engineers and designs specialized process plants for the new world of energy production, including for LNG, waste-to-energy, hydrogen and syngas plants. OnQuest has expertise in execution from engineering and design to delivery, including procurement and turnkey project management and construction supervision. OnQuest also designs direct-fired heaters and waste heat recovery units, burner management systems and clean-air and NOx technologies.

OnQuest's principal offices are in San Dimas, Calif., and Calgary, Alberta, and the company has sales and project offices in Houston, Tex., and San Francisco, Calif. OnQuest has sales representatives worldwide. OnQuest is a subsidiary of Primoris Services Corporation (NASDAQ: PRIM).