Gas escapes through malfunctioning pressure relief valve at Saputo Cheese in Alto

On Friday, February 20, 2026, at approximately 5:30 a.m., the Alto Fire Department was called to Saputo Cheese at N3545 County Highway EE in Alto for a large gas leak.

Upon arrival, fire personnel were directed to the back of the plant where some large natural gas lines were that feed the plant. It was found that one of the lines had a pressure relief valve that stuck open & was releasing a large quantity of natural gas into the air.

Prior to the fire department’s arrival, Saputo had called Alliant Energy & began evacuating all of their employees from the plant, going a few buildings away to the Alto Reformed Church for shelter.

Alto firefighters worked on securing driveways to keep additional employees & contractors from accessing the Saputo property as they were arriving to work.

While making an assessment about whether or not to evacuate any residents from the area, the pressure relief valve stopped leaking. With no more gas escaping, it was determined that it was safe for all residents to remain in their homes.

When Alliant Energy arrived on scene, they were able to shut off the main valve to ensure no more gas would be leaking. Alto fire crews were then sent into the plant, under the direction of Saputo maintenance staff, with gas meters to make sure there was no gas inside the plant.

Ventilation was performed where needed & the plant was turned back over to Saputo employees to return to there operations.

The Alto Fire Department would like to thank Alto Reformed Church for providing shelter for Saputo employees, to Miron construction employees for helping block access to the driveways, to Alliant Energy for a quick response & to the Saputo maintenance employees who helped direct crews through the building.