The Silver Dollar Fire in Benton and Yakima counties was declared 100 percent contained Thursday morning.
The estimate of the burned area was increased on Thursday to 30,984 acres, or about 48 square miles. The fire started Sunday and spread east onto the Hanford Reach National Monument and then onto the main portion of the Hanford nuclear reservation.
Hanford contractor Mission Support Alliance said on Thursday that the fire burned 1,644 acres, or about 2.5 square miles, of the main portion of Hanford, crossing Highway 240 to the west of the southern end of the 200 West Area of central Hanford.
The fire moved to the southeast across land that had not been used for nuclear work, missing the 200 West Area. The 200 West Area includes Hanford’s largest plant for treating contaminated groundwater, the Plutonium Finishing Plant, three plants once used to process plutonium and about 85 underground tanks storing radioactive waste.
The Hanford fire Department cut a disk line around the fire to contain it Monday morning with no contaminated areas burned.
Firefighters off Hanford continued working through the heat on Wednesday to secure the fire perimeter and extinguish burning debris within containment lines.
About 130 firefighters remained at the grass and brush fire site northwest of Richland Thursday. They were patrolling the fire area and extinguishing any hot areas.
Much of the repair work needed for damage caused by fighting the fire was completed Wednesday. Work included smoothing out berms along dozer lines, building water bars on steep slopes to limit erosion and fixing fences cut to allow access to the fire.
Some spots on steep slopes near the Columbia River continued to burn Thursday, but were within the containment area.
Fire officials have received reports of smoke plumes, which have turned out to be dust devils, the columns of dust seen in Eastern Washington in hot, dry weather.
The incident command team plans to turn what remains of the Silver Dollar Fire over to local agencies at 8 p.m. Thursday.