(Reuters) - Twenty-eight preschoolers and two adults mistakenly drank bleach at snack time at a New Jersey day care center on Thursday and were taken to a hospital after some complained their stomachs were burning.

The children, aged 3 and 4, and adult staff members of the Growing Tree Learning Center in downtown Jersey City were transported in five ambulances to the Jersey City Medical Center after a late-morning call to 911, said Mark Rabson, a hospital spokesman. He said some complained of light-headedness, others of upset stomachs.

By mid afternoon, all 30 were in stable condition and were being discharged, Rabson said.

"There was a poisoning and many children were injured," he said, adding the children were walking on their own or were being carried out by their parents and "have smiles on their faces."

Keith Kearney, executive director of United Cerebral Palsy of Hudson County, which runs the day care center that is open to all community members and serves 65 children from infants to age 4, said he had heard no reports of injuries and that the hospital visits were a precaution.

"We had an incident where one of the staff in the kitchen used the cleaning solution bottle to pour water for some of the children," Kearney said.

"It was a repurposed plastic milk jug with a bleach water solution we use to wipe down surfaces. The label we had on the bottle wasn’t large enough to guard against it," he said.

The children and staff were having a morning snack of water and fruit when an adult noticed a faint bleach smell and reported it immediately, he said.

The 911 call kicked off a mass casualty emergency response by the hospital, which called in extra doctors and nurses and worked closely with paramedics, police and fire units.

They gave the victims liquids like water and milk to dilute the poison rather than inducing vomiting "because it would burn on the way back up again," Rabson said.

(Reporting by Barbara Goldberg; Editing by Mohammad Zargham and Peter Cooney)