Candy distributed at a Georgia middle school was blamed after a dozen students fell ill, but authorities said Thursday they have no idea what made them sick.

Several Henderson Middle School students in Butts County reported symptoms “very similar to those of potent THC ingestions” after eating the multicolored hard candies last Friday, according to authorities.

Todd Simpson, the interim superintendent of Butts County Schools, told Channel 2 Action News one student was taken to a hospital by ambulance “out of an abundance of caution.” Parents of as many as a dozen other affected students were contacted, he said.

MORE: Candy that made Georgia middle school students sick likely contaminated at food bank

Sheriff's deputies collected 27 bags of candy from the school and a residence and submitted them all to the GBI Crime Lab for testing. The results showed the candy was completely safe, the Butts County Sheriff's Office said Thursday on Facebook.

“All of the candy was lab tested and no known foreign substance was found,” the sheriff’s office said. “We have no idea what caused those children to become ill.”

The school system has not offered any further statement.

Sheriff’s officials said no child involved in the incident did anything wrong. They initially suspected the candy, which was picked up at a food bank in Hampton, was contaminated. They ruled out any drug or THC lacing quickly, but it was believed some other foodborne contaminant caused the illness.

In February, students at Sandtown Middle School in south Fulton County shared drug-laced treats on Valentine’s Day, sending 28 classmates to hospitals. Students who got sick were disoriented, had stomach and head pain, and red, watery eyes. A school police report also noted hallucinations and vomiting.

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The GBI found THC in a cereal treat eaten by students, which was among 46 food items the crime lab tested. The GBI said the drugs were not detected in any of the other foods collected from the school. Five students faced school discipline in that incident, The Atlanta Journal-Constitution previously reported.

Butts County authorities are encouraging parents to speak to their children about taking candy from an unknown source.

Officials initially said they believed the candy was tainted with THC, but have since said that it did not show any evidence of THC or narcotics.