A dozen students became sick after drinking bottled water from a vending machine at a Southern California junior high school, authorities said.

The students at La Mesa Junior High School in Santa Clarita complained Thursday of headaches, nausea and dizziness after drinking Aquafina water from a vending machine that appeared to contain a "bleach-like substance," said Los Angeles County fire inspector Steve Zermeno.

Twelve students were taken to hospitals and released, Zermeno said. Some of the students reported a chemical smell, he said.

Cody Commons, an eighth-grader who was treated at a hospital, told television station KTLA that the water "was kind of cloudy and it tasted kind of funny," but that he drank it anyway. He said he started feeling cramps "a couple hours later."

The FBI is currently investigating the incident, agency spokeswoman Laura Eimiller said.

The school buys the water from the manufacturer, The Pepsi Bottling Group, and stocks the machines, Principal Pete Fries said Friday. The machines were shut down, he said. The remaining bottled water was pulled and will be replaced with fresh stock.

Jeff Dahncke, a Pepsi spokesman, said there is no evidence the contamination was caused by the company's manufacturing process and Pepsi believes it was an isolated incident.

"We have examined and tasted numerous bottles that were produced at the same time as those in this case and have found them to be free of any problems whatsoever," the company said in a statement. It said it was working closely with authorities to determine what happened.

Aquafina, a leading brand, is bottled at Pepsi plants from public water sources using a seven-step purification process, according to the Aquafina Web site.