Petrolia Fire Department and EMS are responding to the scene of a possible explosion in Fairview Township.
The call came into the Butler County 911 Center just before 1:30 p.m. for an event at the Sonneborn Plant that shook nearby houses.
Units from Chicora, Bruin and North Washington were also called out to assist with a confirmed fire at the hydro plant.
It is unknown if there are any injuries. The cause of the event is also unknown.