Racial and Ethnic Disparities in Liver Disease in the WTC General Responder Cohort: People of color experience persistent disparities in liver disease outcomes in the U.S. This project investigates how these dis- parities may affect members of the Mount Sinai WTC General Responder Cohort. Currently, the WTC Healthcare Program (WTCHP) covers liver cancer treatment, but it does not cover the diagnosis and treatment of other liver diseases or liver cancer surveillance These policies may create holes in the healthcare safety net that could disproportionately disadvantage African American Responders. Fortunately, WTC monitoring visits provide the data needed to calculate the Fibrosis-4 (FIB-4) score, a well-validated instrument for liver disease screening. We embedded a FIB-4 calculator in Mount Sinai’s EPIC electronic medical record (EMR). It is available to Mount Sinai WTCHP providers. In this project, we will introduce the calculator to Mount Sinai WTCHP providers. We will also analyze for disparities in mortality and study archived specimens to assess for toxins that were present in the WTC dust cloud. Environmental and workplace exposures to toxins can cause liver injury and cancer and they synergize with other sources of liver injury to magnify damage and liver cancer risk. The WTC dust cloud contained tons of debris and hepatotoxins, including particulates, polychlorinated biphenyls (PCBs) and other persistent organic pollutants (POPs). Adolescents exposed to WTC dust had elevated PCDD/F levels > 12 years after the attack, establishing that toxins in WTC dust remain detectable for long periods. Our research is expected to show that WTC exposure caused, aggravated, or contributed to liver disease (criteria for certification). Aim I: Disparities in mortality. The goal of SubAim1 is to collaborate with the WTCHP General Responder Data Center to rigorously identify all Mount Sinai WTC General Responders with cirrhosis and/or liver cancer. The goal of SubAim 2 is to test the hypothesis that among responders with cirrhosis and/or liver cancer, African American responders have higher all-cause and liver-related mortality than other responders. Aim II: A FIB-4 calculator to screen for liver disease in Mount Sinai General Responders. The goal of Aim II is to enable WTCHP providers to screen for liver disease. We will introduce the FIB-4 calculator to Mount Sinai WTCHP providers at some clinics and not others and test the hypothesis that education increases use of the calculator. We will also monitor for differences in rates of referral to hepatology between clinics in each arm. Aim III: WTC toxins in plasma and liver. The goal of SubAim 1 is to test the hypothesis that plasma levels of PCBs and other POPs are higher in GRC responders than in controls and are directly related to FIB-4 scores and inversely related to platelet counts. The goal of SubAim 2 is to compare particulates and granulomas be- tween archived liver specimens of WTC responders and con...