A dump truck hit a stop sign and caused a serious crash with an SUV on Route 176 near Union, according to the sheriff's office.

Sheriff's officials say a dump truck ran a stop sign and crashed into an SUV on Route 176 in unincorporated Union on Thursday morning, forcing a woman to be transported flown to hospital with life-threatening injuries.

The McHenry County Sheriff's Office, Marengo Fire and Rescue District and Union Fire Protection District responded at 10:13 a.m. Thursday to Route 176 and Union Road in the unincorporated town Union company for an accident involving two vehicles with injuries.

Firefighters arrived at the scene within four minutes and observed the accident, causing heavy damage, said Alex Vucha, communications specialist for the Marengo Fire and Rescue District.

The crash involved a 2021 Dodge Durango and a 2001 International dump truck, the McHenry County Sheriff's Office said in a news release.

Rescue crews located a female driver – who the sheriff's office identified as a 29-year-old woman from Marengo – unconscious and trapped inside the Dodge SUV.

Firefighters quickly worked to extricate the woman and transferred her to a waiting LifeNet medical helicopter, where she was airlifted to Advocate Condell Medical Center in Libertyville with serious, life-threatening injuries, Vucha said .

Sheriff's officials said the woman's condition has since stabilized.

A dog was also inside the SUV but was unharmed, Vucha added.

The truck driver – identified by the sheriff's office as a 41-year-old man from Mundelein – denied being injured at the scene.

No one else was injured, Vucha said.

The serious crash resulted in the closure of Route 176 between P&O Road and Millstream Road in Union for the investigation.

The preliminary investigation reveals that the Dodge was traveling westbound on Route 176 and the dump truck was traveling northbound on Union Road.

“The International failed to stop at the posted stop sign at the intersection of Route 176 and struck the Dodge on the driver’s side of the vehicle,” the sheriff’s office said.

Both vehicles left the road after the collision and came to rest in an upright position.

Aside from the stop sign, sheriff's officials said there were no traffic control devices at the intersection.

“Both drivers were wearing seat belts and alcohol does not appear to be a factor in the accident,” the sheriff’s office added.

The crash remains under investigation by the McHenry County Sheriff's Office Major Traffic Accident Investigation Unit.