NNSA prepared this special environmental analysis (SEA) to document its assessment of impacts associated with emergency activities conducted at Los Alamos National Laboratory (LANL), Los Alamos County, New Mexico, in response to major disaster conditions caused by the wildfire known as the Cerro Grande Fire. This wildfire burned about 7,650 acres (ac) (3,061 hectares [ha]) within the boundaries of LANL and about an additional 35,500 ac (14,200 ha) in neighboring areas. DOE’s emergency response to the threat of this fire began with certain preventative actions undertaken immediately before the wildfire entered LANL boundaries in early May 2000. DOE’s subsequent actions include those taken to suppress the fire while it burned within LANL boundaries, as well as post-fire activities taken to address the extreme potential for erosion and flood damage at LANL and properties downstream from the facility.