The Ally 400 NASCAR Cup race is in red-flag conditions due to lightning in the area.
A 30-minute stoppage is mandated whenever lightning is detected within an eight-mile radius of the racetrack.
Fans were asked to vacate the grandstands and seek shelter.
Denny Hamlin has led each of the opening 41 laps at the Lebanon, Tennessee, track. Daniel Suárez, the series’ most recent winner, runs second ahead of Trackhouse Racing teammate Ross Chastain, Christopher Bell and Kyle Larson.