OBJECTIVES/GOALS: Particulate matter (PM) and metabolic syndrome (MetSyn) increase risk of World Trade Center-Lung Injury (WTC-LI). Mediterranean-type diets have also been found to improve lung function. Fire Department of New York 1st-responders with a high PM exposure at WTC and MetSyn may have improved lung function after a Mediterranean dietary intervention. METHODS/STUDY POPULATION: Food Intake REstriction for Health OUtcome Support and Education (FIREHOUSE) randomized clinical trial (RCT) assessed our hypothesis that a low-calorie Mediterranean (LoCalMed) intervention targeting clinically relevant disease modifiers will improve metabolic risk, subclinical indicators of cardiopulmonary disease, quality of life, and lung function in firefighters with WTC-LI. Primary-outcome targeted a LoCalMed loss of BMI(≥1kg/m2). Secondary-outcomes included lung function, quality of life, and cardiovascular health. Male firefighters with WTC-LI and a BMI>27kg/m2 were randomized to: 1. LoCalMed (n=46); or 2. Usual Care (UC; n=43). Clinicaltrials.gov:NCT03581006. RESULTS/ANTICIPATED RESULTS: LoCalMed’s estimated efficacy on BMI reduction crossed the pre-specified significance boundary on interim analysis compared to UC. In addition, improvements were observed in secondary-outcomes of lung health (FEV1 and FVC), inflammation (WBC), vascular disease (DBP), quality of life (SF-36, health perception) and dietary habits (less cholesterol, carbohydrates, fats, and sweets and increased protein) in the LoCalMed arm. DISCUSSION/SIGNIFICANCE: LoCalMed significantly decreased BMI and alleviated adverse health outcomes in our WTC-exposed first responders. A fully powered RCT is required to determine if this approach is efficacious for the treatment of WTC-associated pulmonary disease, as well as LoCalMed’s generalizability to PM associated disease.