On December 26, 2019 at 10:33 hrs, Units were dispatched for a Commercial Building fire at the Dahlgren McDonald’s - reported fire in the deep fryer. Rescue Engine 2 AOS to find a 1 story, wood framed,commercial building with nothing evident on sides alpha, bravo, and delta. NDW Battalion 28 AOS and established James Madison Command on the C/D corner of the structure. RE2 reported light smoke throughout the structure and reported a working fire. Crews found fire contained to the deep fryer. Interior crews knocked down the fire with dry chemical and class K extinguishers. Truck 28 began checking for extension. Battalion 1 AOS and assumed the role of Division 1 Supervisor after a face to face with NDW B28. Truck 28’s operator and EMS 1 checked the roof and exhaust hood for extension. Primary search was complete and negative, fire was out with no extension, crews were working to ventilate the structure. Command held the assignment with Rescue Engine 2, Truck 28, Engine 1, Tanker 2, Battalion 1, and Battalion 28. All other units were returned to service. Crews used positive pressure ventilation to assist with smoke removal. Power was secured to the kitchen area at the panel box. After 30-45 minutes of ventilation, smoke was cleared from the structure. Crews determined that the atmosphere was non-IDLH. Store managers were allowed to begin the cleaning process. Employees removed the deep fryer from the structure. Notifications were made to the health department for further action. Managers were made aware that the restaurant was not to reopen until cleared by the health department. No other fire rescue services were needed. Command was terminated and all units returned to service when ready at 11:56 hrs.