FREMONT, Neb. (AP) -- Fire and heavy smoke were still pouring out of a Nebraska biofuels plant Wednesday morning, preventing firefighters from getting close enough to search for three people missing in a huge explosion a day earlier, officials said.

Photos taken after Tuesday's blast at the Horizon Biofuels plant show its tall tower -- marked by a distinctive sunbeam logo of the former owner, Golden Sun Feeds -- torn off, exposing mangled metal and ripped siding. Debris littered the ground, and nearby residents say the blast shook their homes.

"We had a fire going all night, even through the rain," Fremont Mayor Joey Spellerberg said early Wednesday in an interview with the radio station KFAB in Omaha.

"You have the feed mill area, you have the office area just under flames, basically it has not stopped," Spellerberg said. He said authorities believe the three missing people might have been in the office when the explosion happened at around noon Tuesday.

Fremont Fire Chief Todd Bernt said first responders were up against "heavy smoke and a lot of flames" when they first arrived at the facility, which is surrounded by other manufacturing and food processing plants.

The plant makes animal bedding and wood pellets for heating and smoking food, using tons of wood waste, and Bernt said they believe the facility stores wood and some alcohol-based materials. A 2014 fire at the building had damaged the electrical system but left the structure intact, according to reporting by the Fremont Tribune.

Taylor Kirklin, who lives about a half mile (0.8 kilometers) from the building, said her whole house shook Tuesday. She said the explosion was so loud that she thought someone had crashed a car into her family's dog kennel business on the property.

"I got up and looked outside and there was a huge plume of smoke," she said. "We were really unsure when the explosion happened which plant it was, because there are so many in that area."

Dodge County Attorney Pamela Hopkins, who also serves as the county coroner, said law enforcement and first responders were busy securing the scene Tuesday afternoon and had not yet contacted her in her role as coroner. She added that she was hoping not to get that call.

"Right now, we're focused on the safety of the community and getting the situation under control -- keeping the scene secure," Hopkins said. She declined to comment further.

Fremont, a city of about 27,000 and the sixth-largest in Nebraska, is 32 miles (52 kilometers) northwest of Omaha.