Published: Jun 30, 2011 10:00 PM EDT
Updated: Jun 29, 2011 6:18 PM EDT

PORT CHARLOTTE, Fla.- UPDATE: Accidental carbon monoxide poisoning is believed to be what caused a woman and two children to lose consciousness in their car in a Charlotte County Publix parking lot on Wednesday, according to the Charlotte County Sheriff's Office. 

A woman and two children are conscious and under observation at an area hospital after they were found passed out in a vehicle at a grocery store parking lot.

On Wednesday afternoon, the Charlotte County Sheriff's Office received a call that bystanders had found the family in the parking lot of Publix, located at 24123 Peachland Boulevard in Port Charlotte.

Witnesses reported that the woman appeared to be in her 40's, with two young girls in the car with her.

Patrick Moran was one of the people who came upon the scene, and helped pull the kids from the SUV before emergency crews arrived.

"There was a lady at the window of the car on the outside saying, 'I think she's having a heart attack. She's not moving,'" says Moran.

When he opened the car door, he saw the woman passed out in the driver's seat. He says the two girls were limp in the back seat.

"They were just like zombies. They were just not responding at all," he says.

Moran says he and others pulled the girls out and called 9-1-1. That's when he says he noticed the inside of the vehicle smelled odd.

"Kind of pungent. Kind of like when you're in the garage and you start up a car," says Moran.

Emergency workers tested for toxic substances but found none on scene. Still, Hazmat crews hosed down as a precaution.

Authorities are still trying to determine what caused the episode. The car has been impounded at the sheriff's office.

"There is a possible danger for someone to just open a car door if there are unconscious people in it. They could have done harm to themselves as well," says Dee Hawkins, with the Charlotte County Sheriff's Office.

Moran says despite that risk, he didn't think twice about going in to save the children.

"I have four daughters of my own. It kicks in that you need to do something right away," Moran says.