A small burn pile might have been the cause of a hay fire near Union Friday afternoon that sent a column of black smoke into the air.

Fire personnel from the Huntley Fire Protection District said in a news release that it was initially unclear what was on fire when they were called to the 15000 block of Marengo Road outside Union at shortly after 3:30 p.m. for a report of a possible structure fire, but the smoke could be seen in the distance.

Firefighters arrived to find a large hay pile “fully involved in fire, surrounded by several barns,” the release said.

“Crews quickly deployed hose lines and established a rural water supply at the roadway to support firefighting operations,” the release said.

The fire was substantially put out within 20 minutes, preventing damage to nearby buildings, but “firefighters worked extensively to pull apart and soak approximately fifteen large bales to ensure the fire was completely out,” officials said, adding hay fire “can be difficult to fully extinguish due to hidden pockets of smoldering material that can easily reignite.”

Officials said they property owner told them a burn pile nearby might have spread to the bales.

The district in the news release reminded residents “to use extreme caution when burning outdoors, monitor wind speeds, and have a water supply nearby. Even small fires can quickly spread in dry or windy conditions. Always ensure burn areas are located a safe distance from combustibles and never leave fires unattended.”

The response was held to Huntley Fire Protection District units, with assistance from a water tender provided by the Hampshire Fire Protection District. Firefighters remained on scene until approximately 5:30 p.m. performing overhaul operations and extinguishing hot spots. No injuries were reported.