This report provides baseline environmental information for the property identified for possible expansion of the Yakima Firing Center. Results from this work provide general descriptions of the animals and major plant communities present. A vegetation map derived from a combination of on-site surveillance and remotely sensed imagery is provided as part of this report. Twenty-seven wildlife species of special interest (protected, sensitive, furbearer, game animal, etc.), and waterfowl, were observed on the proposed expansion area. Bird censuses revealed 13 raptorial species (including four of special interest: bald eagle, golden eagle, osprey, and prairie falcon); five upland game bird species (sage grouse, California quail, chukar, gray partridge, and ring-necked pheasant); common loons (a species proposed for state listing as threatened); and five other species of special interest (sage thrasher, loggerhead shrike, mourning dove, sage sparrow, and long-billed curlew). Estimates of waterfowl abundance are included for the Priest Rapids Pool of the Columbia River. Six small mammal species were captured during this study; one, the sagebrush vole, is a species of special interest. Two large animal species, mule deer and elk, were noted on the site. Five species of furbearing animals were observed (coyote, beaver, raccoon, mink, and striped skunk). Four species of reptiles and one amphibian were noted. Fisheries surveys were conducted to document the presence of gamefish, and sensitive-classified fish and aquatic invertebrates. Rainbow trout were the only fish collected within the boundaries of the proposed northern expansion area. 22 refs., 10 figs., 4 tabs.