PROJECT SUMMARY The Human Health Exposure Analysis Resource (HHEAR) provides the extramural research community access to laboratory and statistical analyses to add or expand the inclusion of environmental exposures in their research. Through these efforts, the HHEAR-Data Center aims to be a data science resource for the environmental health community, maximizing the potential use, reuse and impact of environmental exposure data. An integral part of this initiative, the HHEAR Data Repository was created to house all data generated within HHEAR labs and provided by HHEAR investigators for epidemiologic and exposure studies within the HHEAR network. Key strengths of this repository are the breadth of high-quality measurements of environmental health data, harmonization of disparate datasets to a common vocabulary and customized downloads that can be saved, stored and shared among users. To augment the Repository’s existing capabilities, we propose two specific aims to enhance the use, utility and impact of the HHEAR Data Repository. First, we will enhance the alignment of the HHEAR Data Repository with the FAIR (Findability, Accessibility, Interoperability and Reusability) Data Principles and the desirable characteristics of data repositories detailed by the National Institutes of Health. We will then develop and implement evaluation metrics designed to align with the FAIR Data Principles. These metrics will monitor use, utility and impact in order to stimulate continuous improvement throughout the lifecycle of the HHEAR Data Repository. To construct our enhancement plan, we conducted self-assessments of the Repository to evaluate its FAIR-ness, desirable characteristics and utility of existing evaluation metrics. These self-assessments revealed gaps in machine-readable metadata to describe the data-generating processes and detailed provenance of datasets from HHEAR studies. Increasing accessibility to metadata, potentially through metadata explorers or application programming interfaces, was identified as another target for enhancement. In addition, self- assessments led to a recognized need for user surveys to augment existing usage metrics generated by monitoring access and downloads within the HHEAR Data Repository. We propose clear milestones to implement these and other planned enhancements during the supplement period. By increasing alignment with the FAIR data principles and expanding evaluation metrics of the HHEAR Repository, we will be able to maximize the benefit of the HHEAR program to the scientific community and provide the data infrastructure for the next generation of exposome science.