ATLANTA (AP) — A multi-vehicle crash that sent large flames and black smoke billowing over a busy interstate near Atlanta has left two people dead and snarled traffic for hours, police said Saturday.

Officials in Gwinnett County said the accident occurred on a northbound stretch of Interstate 85 at about 7:50 a.m. in an area northeast of Atlanta.

Large flames and thick black smoke could be seen rising from the interstate near an exit to another major thoroughfare, Jimmy Carter Boulevard. Police reported a loud explosion was heard in the crash and said a tanker truck and a passenger vehicle were completely engulfed in flames.

A statement posted on the Gwinnett County government website said an “unidentified flammable liquid from the tanker” seeped into a nearby storm drain, causing the fire to spread underground and then up through another storm drain.

“This resulted in multiple fires and large smoke stacks on and around both Interstate 85 northbound and southbound,” the statement said. Fire crews from Gwinnett and Dekalb counties put out the flames.

The Georgia Department of Transportation said the fire damaged five lanes of asphalt along the interstate and that crews were brought in for emergency paving and repairs.

Authorities later tweeted that they had reopened all lanes over the course of several hours on Saturday in both directions.

The interstate is a vital artery through Georgia. A fire beneath an elevated section of the interstate in March 2017 caused a section in Atlanta to collapse. That collapse that year affected 350 feet in each direction of Interstate 85 and further snarled Atlanta’s already notorious traffic for six weeks as the crumpled section was rebuilt.