Texas police say they are still treating the factory in West, Texas, as a crime scene, but said it is routine for them to do so.
The total number of those injured following the explosion has now passed 160, they said.
Any public danger due to chemicals in the air has now gone thanks to the weather in the area, police added.
The death toll is still believed to be somewhere between five and 15.
A major rescue effort is ongoing in a Texas town devastated by a fertiliser plant explosion that has been likened to a nuclear bomb blast.
A huge explosion at a fertiliser plant in the Texan town of West has injured more than 160 people and caused widespread destruction.