The arsonist, a man in his 60s, allegedly made antisemitic comments during his arrest.
The Volga river region's Syzran refinery was on fire but an attack on the Novokubyshev refinery was thwarted, Governor Dmitry Azarov said in a statement on the Telegram messaging app.
"[Bushnell] wanted to light a strong spark, to reignite our cause,” Mayor Abdul Karim Sidr told a small crowd gathered at the opening.
A 65-year-old woman has reportedly barricaded herself in a room, where smoke has been seen, with 'pyrotechnics.'
The wildfire, raging northeast of Amarillo since Monday, has blackened 850,000 acres (344,000 hectares) of grasslands and timber since Monday.
Extremists are threatening to set the mentally vulnerable alight and normalize political violence in America.
The protester was identified as Aaron Bushnell, 25, an Air Force service member. He is reported to have died from his wounds.