ENNIS — The investigation is still ongoing after a pair of accidents occurred one after the other Tuesday on Interstate Highway 45. One of the two sent one person to the hospital.

Troopers with the Texas Department of Public Safety were dispatched at about 6:30 p.m. to a two-vehicle crash on the southbound side of IH45 approximately one mile north of the Navarro County Line.

“Preliminary investigation shows that a 1998 green Peterbilt truck tractor towing a 2011 silver Stephens semi-trailer was traveling south in the middle lane. When, for an as of a yet determined reason, the truck-tractor drove into the left lane causing a 2012 white Toyota Rav4 sport-utility vehicle to drive off the roadway,” DPS Public Information Officer Sgt. Sara Warren said. “The Toyota rolled and came to rest in the center median.”

The driver of the truck-tractor, 35-year-old Carl Buckley III, of Camden, Oklahoma, was not injured. The driver of the Toyota, 19-year-old Chloe Oesterreich, of Sugar Land, was also not injured.

The truck-tractor was transporting ammonium nitrate, which is a hazardous material, but no hazardous material was released.

“In the traffic backup from the initial crash, a 2013 black Freightliner truck tractor towing a 2015 silver Hyundai semi-trailer was traveling south in the right lane,” Warren stated. “For, an as of a yet determined reason, a 2010 white Chevrolet 2500 pickup truck failed to slow down and struck the rear of the semi-trailer.”

Warren said the driver of the truck-tractor, 49-year-old Michael Leichty, of Canton, was not injured. The driver of the pick-up truck, 62-year-old Jerrel Hinton, of Pasadena, was transported to Parkland Memorial Hospital in Dallas by air ambulance with serious injuries. The cause of the accident has not been determined at this time.