A fire crew was conducting a contained burn on the propane tank that sparked a massive fire earlier this week at a closed Norfolk manufacturing plant.

The 30,000-gallon tank was being emptied of its contents on Saturday, and the crew was burning off the residual vapors.

City officials were advising residents not to worry.

Several thousand people were evacuated Thursday morning before the fire was safely extinguished.

The Norfolk fire department has said a regulating valve near the tank failed and allowed gas to vent in the air. That gas was ignited by a pilot light near the north end of the tank and spawned tall plumes of bright orange flames that threatened the tank itself.

Propane fire video courtesy of Northeast Community College