(NewsNation) — A massive wildfire in central California has burned more than 125,000 acres, according to authorities.

The Gifford Fire originated in the city of Solvang, about 15 miles northeast of Santa Maria, and was 37% contained as of Tuesday, fire officials said.

The blaze has destroyed four structures and is threatening more than 800. Seven people have been injured, and at least 780 residents have been evacuated, fire officials said.

More than 4,000 personnel are working to battle the fire, which began as four smaller blazes along California’s Route 166 on Aug. 1 before merging into one. The fire’s cause remains under investigation.