(FOX40.COM) — CAL FIRE officials announced on Thursday that a man was arrested shortly after the Thompson Fire started burning after allegedly starting a second blaze to try to contain the main one. The 61-year-old man, a resident of Oroville, was detained on the afternoon of July 2 several hours after the Thompson Fire began around 11 a.m. that same day. CAL FIRE officials said the man was arrested after admitting he had set a backfire with a propane torch. A backfire is a fire set on purpose that can be more easily controlled and serves as a way to burn vegetation so that a larger fire cannot advance any farther. CHP recovers $50,000 in stolen goods from Northern California warehouse However, CAL FIRE officials said that the fire the man created posed a risk to the public and personnel working to contain the Thompson Fire. The man was charged with unlawfully causing a fire to wildland. As of Thursday evening, the Thompson Fire was nearly 4,000 acres in size, about the size of a university campus, and was 29% contained. More than 20,000 people remained displaced due to evacuation orders.