A fire at a refinery in El Dorado is what caused at least two explosions that shook people's homes Wednesday morning, an official says.

Butler County Sheriff Kelly Herzet confirmed the reports of explosions at the HollyFrontier refinery at 1401 Douglas Road. People in the area called KAKE News and reported on social media that their homes shook and thick black smoke could be seen for miles. 

Liberty Swift, communications manager for the refinery, said there was a fire in a pipe rack at around 8 a.m. She said the plant's emergency response team responded and safely contained the fire. No one was hurt. 

"Our employees and contractors are accounted for and safe," Swift said. "As a precaution, we also evacuated all non-essential personnel. We will continue to monitor the surrounding area and do not expect the community to be affected."

Sheriff Herzet said county law enforcement and fire officials did not respond to the scene and that the incident was under control.