RICHLAND – A wildfire burning toward the Hanford nuclear reservation scorched about 110 square miles of brush and grass Monday as it spread from Yakima County into Benton County.

The blaze, the largest of several wildfires in Central and Eastern Washington, began Saturday on the U.S. Army’s Yakima Training Center and quickly grew in size over the weekend.

But fire lines set overnight and low winds Monday are helping to slow the fire’s progression, said Randall Rishe, a spokesman with the U.S. Bureau of Land Management. The cause is being investigated.

Crews were able to keep the fire west of Highway 240 by burning up grass and other fuel along there, he said, and away from contaminated areas within the 586-square mile Hanford site north of Richland. Hanford once made plutonium for nuclear weapons and is now undergoing a decades-long cleanup.

“We do not see it progressing any further east,” Rishe said. “Our containment lines are in place, the burnout was successful on Highway 240, so the potential for fire danger in that area is very low at this time.

A section of State Route 24 near Hanford that had been closed also reopened Monday, a state transportation official said.

The Department of Energy said Monday on its website that Hanford work schedules weren’t affected at this time.

Meanwhile, fire crews were fighting another blaze that scorched more than 9 square miles of grassland outside of Prosser.

Local crews were able to protect homes threatened by the fire, and all evacuation orders were lifted Monday morning, said Marcus Deyerin, a spokesman with the Northwest Washington Incident Management Team. One outbuilding burned.

Emergency shelters that opened in Yakima County to response to both fires are now closed, said Kent Katlin, a spokesman for Yakima County Emergency Management.

Several campgrounds along the Naches River were evacuated Sunday evening as a wildfire burned in thick forest about 25 miles west of Yakima, said U.S. Forest Service spokeswoman Robin DeMario.

About 100 people at Camp Roganunda, a Christian camping facility, and others at two federal campgrounds were told to leave the area, and an additional 25 homes in the area were also evacuated, DeMario said.

State Route 410 remained open but travelers are advised to be careful because of firefighting operations in the area.

No structures have burned and no injuries have been reported. The cause of the 100-acre fire, which started Sunday evening, is under investigation, DeMario said.

BLM’s Rishe reminded people not to operate drones in the area of wildfires. He said air operations were temporarily halted Saturday because of concerns that a drone would interfere with firefighting activities.

“If you fly your drone, we can’t fly our plane,” he said.