The purpose of this project is to assess the technical basis and the numerical values for the Airborne Release Fractions (ARFs). These ARFs are used in both facility categorizaion and detailed accident analysis to estimate accident dose consequences for U.S. Department of Energy (DOE) nuclear facilities. The DOE standard (DOE 1997) on hazard categorizaion and accident analysis techniques known as DOE-STD-1027 does not address several forms of material encountered by the Office of Environmental Management (EM) at the various DOE sites. In early 1996 DOE attempted to establish and standardize ARF values across the EM complex by developing the EM Facility Hazard Categorization Standard (DOE 1996a,DOE 1996b), known as SAFT-0029, which included specific ARF values. However, SAFT-0029 was never finalized. The ARF numerical values included in SAFT-0029 are recognized and used by some DOE sites, but other DOE sites have been chosen to use only DOE-STD-1027 ARF values or to develop and use their own values based on their analyses and specific situations. The significance of ARF is derived from its contribution to the source term, which in turn is a key parameter for estimating the scope of the potential release spectrum from a facility or an activity and potential downwind consequences.