A U.S. Forest Service firefighter was killed by a falling tree while battling a blaze in the Lake Tahoe area on Saturday, officials said.

“It is with great sorrow we must confirm the loss of a U.S. Forest Service wildland firefighter this evening in the Lake Tahoe area,” the agency said in a statement released late Saturday. The firefighter, who was not immediately identified, died around 5:30 p.m.

The incident occurred at a new wildfire burning in a remote area with rugged terrain between Lake Tahoe and the Eldorado National Forest and south of Echo Summit, according to the agency. The fire, reported at about one-tenth of an acre and likely caused by lightning, was 75 percent contained as of Saturday. Firefighters with both the California Department of Forestry and Fire Protection and Nevada Division of Forestry also responded to the blaze.

A second firefighter was injured but was taken to a hospital and later released.

The firefighter’s death is the second in California during this fire season. In late July, a U.S. Forest Service firefighter, David Ruhl, died of smoke inhalation and carbon monoxide poisoning while battling the Frog Fire in Modoc County.

Across the state, more than 10,000 firefighters are battling 18 wildfires, according to the Cal Fire. More than 2,000 firefighters continue to battle the 69,636-acre Rocky Fire near Clear Lake about 110 miles north of San Francisco. The blaze was 70 percent contained early Sunday, a day after all evacuations in the area were lifted.

The cause of the fire is under investigation. Firefighters hope to secure full containment by Thursday.