The UCR Radiocarbon Laboratory Project completed the cataloging of 5,688 samples of primarily wood, charcoal, soil, shell, animal bone, and a small number of human remains found in the boxes of samples submitted to the former UCR Radiocarbon Laboratory for radiocarbon dating on December 18, 2021.

The records of the UCR Radiocarbon Laboratory, which included the remaining samples from three predecessor laboratories - the UCLA Institute of Geophysics and Planetary Physics Radiocarbon Laboratory, the University of Chicago Radiocarbon Laboratory of Dr. Willard Libby, and the UC San Diego Mt. Soledad Radiocarbon Laboratory - were transferred to the UCR University Archives by the former director of the UCR Radiocarbon Laboratory, Dr. R. Ervin Taylor in 2016. University Archives staff discovered that samples from all four laboratories were commingled with the records in approximately 30% of the boxes.

The project staff has already returned 83 of the 137 NAGPRA-covered human remains to the responsible institutions or researchers so that those institutions can begin consulting with the appropriate tribes for repatriation of those ancestral remains. The project staff have also arranged for an additional 11 remains to be couriered to the responsible institution and is working with three other institution to coordinate the return of an additional 24.