Explosion at Nebraska biofuels plant leaves three missing, area on lockdown.

An explosion at a Horizon Biofuels plant in Fremont, Nebraska, occurred on Tuesday, leaving three people unaccounted for. The plant, which produces fuel pellets and animal bedding, experienced significant damage, preventing access to the building. Multiple emergency services responded, and a three-mile radius around the site has been blocked off for safety. The cause of the explosion is under investigation.