ClearSign Technologies Corporation (NASDAQ:CLIR) ("ClearSign" or the "Company"), a leader in advanced combustion and sensing technologies that help industrial operators dramatically reduce emissions, increase efficiency and support the use of cleaner fuels including hydrogen, announces that it has received a purchase order for the physical testing and demonstration of burners as the second phase of a process heater retrofit project comprising of a total of 32 ClearSign Core™ burners to be installed in the customers California refinery.

"We are pleased to have completed the initial engineering and computational simulation for this large project for a major refinery in the California market, and to now move into testing and demonstrating the physical burners at Zeeco's full-scale test facility," said Jim Deller, Ph.D., Chief Executive Officer of ClearSign. "This is particularly exciting as these burners will be another configuration of our new Core 2 technology, a flat flame application, which will further expand our addressable market to include new refining heater types."

"This project advancement follows a highly successful group demonstration held in Tulsa just weeks ago for key decision-makers, existing customers, and prospective clients. The strong attendance and positive feedback reinforced our belief that market awareness and acceptance of our innovative burner solutions for the refining and petrochemical industries continues to grow."

"We believe that completing this project will serve as additional validation of our highly configurable burner platform and will demonstrate both the scalability and practical application of our technology in different operational environments."

This order follows the initial CFD and engineering order that was received from this customer and announced on October 7, 2025.