UPDATE: Texas DPS providing additional details on the fatal 18-wheeler crash that occurred Monday evening in Rancho Viejo.

The initial investigation from Texas DPS revealed the 18-wheeler was transporting hazardous-flammable material traveling northbound on Toll Road 550 at an unsafe speed.

The driver lost control of the vehicle, causing it to strike a concrete barrier and roll on its side.

The deceased has not been identified, according to the news release from DPS.

Texas DPS Sgt. Maria Montalvo is asking if anyone witnessed this fatality as it occurred, to call the Weslaco DPS Office at 956-565-7600.

RANCHO VIEJO, Texas (ValleyCentral) — One person is dead after an 18-wheeler overturned on the toll road near Rancho Viejo and burst into flames.

According to Lt. Martin Sandoval, public information officer for the Brownsville Police Department, the tractor-trailer overturned on Toll Road 511 at the interchange with Expressway 77.

Fireballs shot into the air as the fuel from the trailer burned out of control. The smoke could be seen from as far away as Harlingen.

Traffic on the expressway was backed up in both directions as police tried to redirect motorists to side streets. Sandoval said the cause of the accident is still unknown.

Firefighters could be seen trying to battle the massive blaze, but the fuel in the trailer only exacerbated the problem.

ValleyCentral will provide more details as they become available.