AUSTIN, Texas — A Lake Travis fire truck driver on Wednesday afternoon suffered a medical emergency and lost consciousness, causing him to veer into oncoming traffic, leading to a fiery crash that sent nine people to the hospital, the Texas Department of Public Safety said in a statement.

5 cars and a fire truck from Lake Travis Fire and Rescue involved

Driver of fire truck lost consciousness, veering into traffic

Firefighter driving and one other driver in serious condition

The fire truck was traveling south on FM 620, north of Comache Trail when the Engineer William Tatsch, a nearly 20-year veteran, suffered a medical emergency and lost consciousness. Up to this point, he had no history of medical emergencies while driving, and officials say what happened to him physically on Wednesday is still unknown. Further medical testing is being done to determine what happened.

The truck, carrying Lt. Rachel Zambrano, and firefighters Brian Baker and Joel Niemeyer, drove into the northbound lanes and struck five vehicles before rolling on its right side. The truck came to rest on its right side, facing south, in the northbound bar ditch.

One civilian driver was taken to Dell Seton downtown with serious injuries. The five other civilians were transported with non-life-threatening injuries. And two other vehicles were struck by debris that flew from the fire truck.

As of 9 a.m. Thursday, Lake Travis fire officials updated that Tatsch remains hospitalized in stable condition. Zambrano was riding on the side of engine which rolled into the ground and was struck by multiple pieces of debris and fire gear in the collision. She suffered a concussion and needed seven stitches to her forehead. She was released Wednesday, but faces a long recovery.

Baker and Niemeyer were treated for minor injuries, and released Wednesday afternoon.

TEXT ALERTS | Sign Up For Breaking News/Weather Updates

Austin police, Travis County Sheriff's Office, Austin Fire Department and Austin-Travis County EMS worked the scene. The conditions of the civilian drivers is not known at this time.

#LTFirefighters Media Advisory - One Firefighter still hospitalized, Collision Investigation Underway



Media: St. David’s Round Rock Hospital, Main Entrance, any time after 9:30.



Press Release Attached. Contact (512) 413 - 6953 pic.twitter.com/iKO2QT1sxy — Lake Travis FF (@LTfirefighters) May 17, 2018

Viewer Shelley Kliefoth shared these images: &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;nbsp;

Update Vehicle Rescue FM 620 and Comanche Trail. 5 cars and Firetruck from Lake Travis Fire/Rescue involved in collision. FM 620

Blocked all directions. Expect VERY major delays see @ATCEMS for patient information pic.twitter.com/sCerNst6Bm — Austin Fire Info (@AustinFireInfo) May 16, 2018

Thoughts and prayers are with our @LTfirefighters brothers and sisters. We wish all involved a speedy and full recovery. https://t.co/eAQyBEcyhZ — Cedar Park Fire Assoc (@CPPFFA4233) May 16, 2018 <_script charset="utf-8" src="https://platform.twitter.com/widgets.js">