All 22 Austin High School students who were taken to hospitals Friday had returned home and were recovering Saturday. No students were hospitalized overnight.
Students say the majority of the ill students were on the dance team. Others were members of the band and color guard. They became ill during the second half of Friday night's game against Yates High School at Barnett Stadium.
Officials said it happened just after halftime, shortly before 9pm. Part of the stadium had to be evacuated while a decontamination zone was set up for sick students.
Symptoms included nausea, vomiting, difficulty breathing, coughing and a scratchy throat.
Austin High band member Ezequiel Galvan said he felt it coming on early.
"I turned like this, then like that, and right when I was about to play, I couldn't play because I felt like gagging," Galvan said.
He was able to perform, but just as Austin High dance team member Brittney Banda finished the show, she and two other dancers became shockingly sick.
"I couldn't breathe and I just started throwing up," she said.
Several Houston ISD administrators and staff members first responded to the situation and were on scene, officials said, including athletic directors and medics.
The Houston Fire Department investigated by taking chemical readings in the area, but nothing was detected by their monitors. Once they gave the all-clear, the football game continued and the affected students were rushed to five area hospitals. Some were hooked up to oxygen and IVs.
No one in the stands was affected.
One firefighter was also treated, but was OK and we're told he drove some of the patients to the hospital.
On Saturday, the HazMat team again reported no readings on any monitors for any substance at the scene. Tests for chemicals in the air and on the students' band instruments also came back negative.
Parents say they are still worried and now have more questions than answers.
A doctor from the EMS service said they were interviewing patients late Friday to try to find any links.
"The kids all ate at different places, some of them ate at different times... but they did have something in their stomachs. At this point, it remains a little unclear what set it off," Dr. David Purse said Friday. "It's still a mystery right now."
Parents said Saturday that doctors discovered high levels of toxins in their children's blood. For Galvan, the diagnosis was chemical inhalation. He was treated for carbon monoxide poisoning. His discharge papers from the hopital state that he suffered chemical inhalation and should follow up with a physician next week.
Galvan's father, who is also a band chaperone, says the hospital told him there were likely high levels of carbon monoxide in the air. He added that HISD has agreed to cover their medical costs.
The mystery behind what caused this incident remains, and HISD police are still investigating.
HFD spokesperson Patrick Trahan said Saturday that their investigation will pick back up on Monday after they have results from the doctors of all students involved.
A football game at Barnett Stadium was relocated Saturday. Officials said no games will be held at Barnett until the source of contamination is identified.
Stay with Eyewitness News and abc13.com for the latest on this story.
