OMAHA, Neb. — A large fire that raged through a Nebraska chemical plant was extinguished by firefighters Tuesday morning, and nearby residents who were initially evacuated were allowed to return to their homes, authorities said.

Thick smoke, billowing from the Nox-Crete facility just southwest of downtown Omaha on Monday evening, could be seen as far away as the Elkhorn River, about 20 miles to the west.

Battalion Chief Scott Fitzpatrick said the first call for help came shortly before 7 p.m. Monday, and firefighters who initially entered the building found a much bigger fire than anticipated, forcing them to retreat.

Fire crews then fought the fire from outside the building, noting the presence of chemicals and propane bottles inside. Explosions could be seen and heard as propane tanks ruptured.

No injuries were reported from the fire or explosions. Officials said the smoke posed no major toxicity risks to the public.

The cause of the fire wasn’t immediately known.

Those living nearby were initially encouraged to shelter in place, but an alert sent just before 9 p.m. urged some residents to evacuate. The nearby Columbus Community Center was opened as a temporary shelter for evacuees.

Omaha Public Power District said more than 2,500 customers were without electricity in the neighborhoods near the fire Monday night, but power had been restored to all but a handful of customers by Tuesday morning.

Representatives from the Nox-Crete chemical company could not be immediately reached for comment.