At least 13 vehicles were hit by the 18-wheeler about 11:30 a.m. Saturday. Several people were taken to the hospital with various injuries.
Authorities say six people had to be transported to the hospital by ambulance. Two others, one of who was driving this 18-wheeler, had to be transported by Life Flight.
"He came off the freeway, went down the embankment then entered the feeder, going southbound on 249," Harris County Sheriff's Office's Senior Deputy Thomas Gilliland said.
From there, the midstream transportation truck hit at least 13 vehicles.
It was carrying non-odorized flammable gas, but so far, appears to be contained.
SA hazmat crew was called to make sure there were no leaks or breaks in the tanker and was structurally sound enough to haul away.
Eyewitness News reached out to the truck company to see if we can find out who the driver is or learn anything about the crash, but received no answer.