Track medical director Bobby Lewis said none of the injuries was life-threatening but two women were airlifted to Birmingham hospitals. Lewis said one, who was taken to UAB Hospital, likely had a broken jaw and also had a cut on her mouth. The other was transported to Brookwood Hospital because of an unspecified medical condition but was not hurt.
Lewis said they were airlifted because of traffic, not the severity of the injuries.
Edwards was trying to block a move from race winner Brad Keselowski, and contact sent his spinning car over Ryan Newman's hood and into the fence on the frontstretch.
The fence held and Edwards' car landed back on the track, but it still caused quite a scare.
The other injured fans were treated and released, with two choosing to seek treatment locally from their own doctors, track spokeswoman Kristi King said. It wasn't clear if the fans were hit by debris from the car or the fence.
"The fence was damaged and pieces of that were flying," Lewis said.
NASCAR spokesman Jim Hunter, sitting near a pile of twisted metal that came off Edwards' car, said his first thought when he saw it headed toward the fence was, "I hope nobody's hurt."
"No. 1, Carl. No. 2, the spectators. It was a sigh of relief when the car came back on the (track)," Hunter said. "I think that's the first time that fence has been hit."
Keselowski emphasized he was thankful that no one was seriously injured, but said there is some entertainment value to crashes.
"I don't want to wreck anyone, but to say a no-contact sport is fun, I don't buy that," he said. "These guys want to see contact just as much as I want to give it and take it."
Some fans agreed. Asked if the wrecks were part of the show, Tim Apfel of south Florida said, "The last two races were great. I hate to say it that way."
His friend, Will Klima, said that he's certain high-speed crashes are scary for drivers, "but when they get out of the car, you see why they spend so much to protect them."
As for the fans, Klima said he feels safe sitting in the grandstands.
"I wouldn't come here if I didn't. The fence is high enough and they put you far enough away," he said, adding: "Things happen."
Jack Roush, the owner of Edwards' No. 99 Ford, said it brought home the responsibility for keeping everyone involved safe.
"I am worried about hurting somebody on my team, about hurting somebody - and I'm talking about pit road and our crew men and mechanics," Roush said. "I carry a great burden, a great responsibility to keep my people safe and, in a broader sense, I feel a responsibility to do no harm to the spectator public. But this is a high-risk environment here."