The National Institute for Occupational Safety and Health (NIOSH) supports research projects that address: (1) physical and mental health conditions related to the September 11, 2001, terrorist attacks; (2) diagnosing conditions for which there has been diagnostic uncertainty; and (3) treating conditions for which there has been treatment uncertainty. Conditions may have emerged since the treatment program began or since the WTC Health Program was established. This announcement solicits meritorious and scientifically rigorous applications that will: 1) improve diagnosis and treatment activities of the WTC Health Program; 2) expand knowledge about health effects related to the September 11, 2001, terrorist attacks; 3) answer critical questions about WTC-related physical and mental health conditions; and 4) apply lessons learned to improve response to future disasters. Potential projects may include, but are not limited to: (a) Screening research to evaluate current methods or facilitate the development of new or improved methods to detect disorders or health conditions; (b) Diagnostic research to evaluate current methods or facilitate the development of new or improved methods to identify diseases, disorders, or conditions; (c) Treatment research to evaluate or identify improved treatment interventions or methods, or to promote development of new or novel approaches; (d) Prevention research to identify or evaluate methods and interventions that prevent or mitigate the development or recurrence of diseases or disorders; (e) Quality of life research to identify, develop, or evaluate methods or interventions that improve comfort and quality of life for individuals with chronic illness or multimorbidity; (f) Omics research to improve methods for predicting disorders by identifying and understanding relationships between genes and illness (e.g., phenotypes and biomarkers), including how genetic factors influence disease development or response to treatment; (g) Epidemiologic or clinical research to identify patterns, causes, and control of adverse health effects among the 9/11-exposed population; (h) Health services research to examine access to care, cost of care, and outcomes associated with care delivery; (i) Implementation research to evaluate how research findings are disseminated, adopted, implemented, sustained, and scaled in real-world settings; and (j) Epidemiologic research to investigate emerging conditions where preliminary data suggest, but do not confirm, a causal relationship between 9/11 exposure and the condition. Examples can be found at https://www.cdc.gov/wtc/received.html.