Scientific data age, become stale, fall into disuse and run tremendous risks of being forgotten and lost. These problems can be addressed by archiving and managing scientific data over time, and establishing practices that facilitate data discovery and reuse. Metadata documentation is integral to this work and essential for measuring and assessing high priority data preservation cases. The International Council for Science: Committee on Data for Science and Technology (CODATA) has a newly appointed Data-at-Risk Task Group (DARTG), participating in the general arena of rescuing data. The DARTG primary objective is building an inventory of scientific data that are at risk of being lost forever. As part of this effort, the DARTG is testing an approach for documenting endangered datasets. The DARTG is developing a minimal and easy to use set of metadata properties for sufficiently describing endangered data, which will aid global data rescue missions. The DARTG metadata framework supports rapid capture, and easy documentation, across an array of scientific domains. This paper reports on the goals and principles supporting the DARTG metadata schema, and provides a description of the preliminary implementation.