Updated at 3:20 p.m.: Revised to report that the highway has reopened.

For the first time in almost a decade, the High Five interchange was entirely closed early Thursday when a semi tipped over, miring a quarter of a million commuters in traffic hell.

The torment finally ended shortly after 3 p.m., almost 12 hours after the rollover, when Central Expressway was finally reopened.

The gridlock began with a relatively routine crash about 4:20 a.m.: A speeding tanker truck full of highly flammable resin crashed on a ramp connecting U.S. Highway 75 and Interstate 635.

Update: Crews are still working to clear the scene of the flipped tanker truck. 75 north and south are still CLOSED. 635 has reopened. Photo from @DallasFireRes_q pic.twitter.com/Cdgh99ESh1 — Madison Sawyer (@MadisonSawyerTV) June 21, 2018

Only a small amount of the substance spilled from the tanker, but the crash ended up delaying the workday of tens of thousands of commuters.

It was one of the first complete closures for the 13-year-old multilevel interchange — which carries 260,000 commuters daily — state Department of Transportation officials believe.

"We were picking brains around here," TxDOT spokeswoman Donna Simmons said, and no one can remember it happening before.

The High Five was closed briefly in 2009 during an ice storm, but until today had not been shut down because of a traffic incident.

The ONLY lanes of #HighFive open are the following:

-635/LBJ Eastbound

-Ramp from 635 West to 75 North



**Still No ETA on when 75 North, 75 South, or 635 West will reopen** pic.twitter.com/AZdHFM9BgK — Madison Sawyer (@MadisonSawyerTV) June 21, 2018

A preliminary investigation suggests that the liquid resin shifted inside the 18-wheeler and caused it to overturn, police spokesman DeMarquis Black said.

According to Black, the driver was travelling at an "unsafe speed" for the curve of the ramp and lost control. The driver was not under the influence of drugs or alcohol, he said.

Firefighters used a ladder truck to spray down the tanker and keep it cool in the heat of the first day of summer.

Dallas Fire-Rescue spokesman Jason Evans said that “out of an abundance of caution,” the High Five was shut down in case the tank began to leak.

"There were no other vehicles involved, nor was there any ... injuries," he said. "However, the tank was in a position that could compromise its integrity if moved.”

Progress Report - First step in the clean up process is off loading the remaining fuel from the jack-knifed tanker truck, once the fuel is transferred then officials will be able to upright the tanker truck. pic.twitter.com/XTXZECLtTl — KRLD Traffic (@krldtraffic) June 21, 2018

The tanker belonged to TransWood Inc., based in Omaha, Neb. A spokesperson for the company could not be reached for comment Thursday.

Heavy rush-hour traffic slowed the process, which involved getting another tanker to offload the resin, Department of Transportation spokeswoman Donna Simmons said.

1 / 8Motorists try to exit to southbound Highway 75 at the Midpark exit, as the access road stacks up to travel on Spring Valley Road after the Intersection of Interstate 635 and Highway 75 north of downtown Dallas was closed because of an overturned truck carrying hazardous materials.(Louis DeLuca / Staff Photographer) 2 / 8A tanker ferrying a "highly flammable" resin rolled on its side about 4:15 a.m. on the ramp from southbound Highway 75 to eastbound LBJ Freeway in Dallas on Thursday morning.(Staff / Paul O'Donnell) 3 / 8The Intersection of Interstate 635 and Highway 75 north of downtown Dallas remains closed after an overturned truck carrying hazardous materials crashed. Photographed on Thursday, June 21, 2018. (Louis DeLuca/The Dallas Morning News)(Louis DeLuca / Staff Photographer) 4 / 8The Intersection of Interstate 635 and Highway 75 north of downtown Dallas remains closed after an overturned truck carrying hazardous materials crashed. Photographed on Thursday, June 21, 2018. (Louis DeLuca/The Dallas Morning News)(Louis DeLuca / Staff Photographer) 5 / 8The Intersection of Interstate 635 and Highway 75 north of downtown Dallas remains closed after an overturned truck carrying hazardous materials crashed. Photographed on Thursday, June 21, 2018. (Louis DeLuca/The Dallas Morning News)(Louis DeLuca / Staff Photographer) 6 / 8The Intersection of Interstate 635 and Highway 75 north of downtown Dallas remains closed after an overturned truck carrying hazardous materials crashed. Photographed on Thursday, June 21, 2018. (Louis DeLuca/The Dallas Morning News)(Louis DeLuca / Staff Photographer) 7 / 8The Intersection of Interstate 635 and Highway 75 north of downtown Dallas remains closed after an overturned truck carrying hazardous materials crashed. Photographed on Thursday, June 21, 2018. (Louis DeLuca/The Dallas Morning News)(Louis DeLuca / Staff Photographer) 8 / 8CORRECTS BYLINE FIELD TO LOUIS DELUCA, NOT PAUL O'DONNELL - A fuel tanker truck sits overturned atop an elevated exchange along the eastbound ramp of Interstate 635 in Dallas, Thursday, June 21, 2018. The High Five interchange of U.S. Highway 75 and Interstate 635, including all ramps was shut down most of Thursday morning. (Louis DeLuca/The Dallas Morning News via AP)(Louis DeLuca / AP)

By 10:30 a.m., six hours after the crash, only eastbound LBJ had been reopened. Some westbound lanes opened by noon, and Central was opened shortly after 3 p.m. Only the ramp where the crash happened remained closed.

A small portion of what drivers are dealing with on US 75 and I-635.

⚠️ Crews concerned for safety bc of gas in the wrecked tanker on High Five

⚠️ Expected to last for hours

⚠️Watch Live here & we have alternate routes https://t.co/M3gsz1gK22 #DFWTraffic pic.twitter.com/LtqgFIsS82 — Eline de Bruijn (@debruijneline) June 21, 2018

Many motorists took to Twitter to express their emotions — good, bad and bemused — using the hashtag #HighFiveShutdown.

Tweets circulated of the hero who made a Whataburger run and the food truck owner who opened the doors to hungry drivers.

This morning, a heroic food truck fed drivers stuck on the highway during the #HighFiveShutdown. https://t.co/fBfNCEHfSk pic.twitter.com/mh29YKeJZ4 — Eater Dallas (@EaterDallas) June 21, 2018

Some drivers shared their podcasts and playlists, while others shared their urgency to use a restroom or have a sip of water.

Jennifer Price of Kennedale was stuck with her boss for more than two hours near TI Boulevard. She said she saw a man in a utility truck disrobe to beat the heat.

“He just took his pants off and drove with the door open,” said Price, 28. “We also saw one person get out of their car and just start walking up the highway.”

Richardson police helped redirect traffic to help drivers navigate around the High Five.

Department spokesman Kevin Perlich said the rollover was a "different situation, because it happened on a ramp and required a hazardous materials team to respond.

“Some people were obviously frustrated and upset, others are appreciative that you’re out there doing the best you can,” he said. “There’s only so much you can do, especially here where there's no way around it.”