HOUSTON – Dozens of students were sickened Thursday morning at a Midtown-area school, according to the Houston Fire Department.
The incident happened at the Young Women's College Preparatory Academy at Cleburne and Chartres streets.
At least 50 students were taken to the hospital with headaches, stomachaches and breathing problems.
The school, with an enrollment of more than 500 students, was evacuated as a precaution. Sky 2 aerials showed dozens of people outside the school.
"They just told us to come out. We came out and they told us to go back in. We went back in. It was really, really bad. Like rotten eggs really bad," student Danteyh Reedy said. "People started going into the ambulance, and fainting and throwing up red stuff. Bad."
A Hazmat team with gas detection meters cleared the building around 1 p.m. and no hazards were found, according to HFD.
VIDEO: Aerials of students sickened at school
The Houston Independent School District said the campus is undergoing renovations and officials are still investigating the source of the smell.
"At this point we’re not sure what the principal reported smelling or what the students reported smelling that was causing the symptoms," Sheldra Bringham, with HFD, said.
CenterPoint Energy said there was no gas leak, which is the way the call was originally reported by HFD.
An inspection team from CenterPoint Energy later determined the cause of the smell was hot tar being used in construction on the building's third floor.
School officials said they contacted parents to let them know school is out for the day. Students not taken to the hospital were being picked up at the old Debakey High School.
"We don’t know what’s going on so we’re just going to take her to the hospital," one student's father said.
Twenty-one students were taken to Texas Children's Hospital by bus just before 1 p.m. As of Thursday evening, all but three had been discharged.
Children's Memorial Hermann received around 30 patients over two campuses and said all will be discharged Thursday.