SAND SPRINGS, Oklahoma - Sand Springs Public Schools says Clyde Boyd Middle School will be closed on Thursday, after two days without classes because of a carbon monoxide leak.

On Wednesday the district defended their response to the leak while at the school, repairs and inspections continued. 

The work was on the rooftop, and all around Clyde Boyd Middle School, where classes were out and the heat was off. Two days after the building was evacuated the district says carbon monoxide detectors are in place and new procedures are on the way.

"One of the things we're going to write into procedures for next year is prior to the units being turned on, to have them inspected before winter and before we have to use them," said Sand Springs Superintendent Sherry Durkee.

Many parents are questioning the district's response to having so many students, with the same symptoms, sick for hours before the evacuation was ordered.

"I got really scared at first because I didn't know what was happening and I didn't know why everyone didn't feel good," said 8th grader Skylie Simpson.

Skylie Simpson and Skyler Cannon say students were vomiting and passing out well before outside help arrived.

"Just seeing people pass out, that was the scariest thing. And I went into the office and there was throw up in the trash can, and it was like people were getting sick and leaving and it was crazy how much it was," said Cannon.

The fire department ordered the evacuation within five minutes of arrival, but that was three hours after students started getting sick. The district had carbon monoxide detectors only in kitchens, but they were installed at Clyde Boyd on Wednesday.

"We knew something was going on, it was odd, everybody was getting sick," said Simpson.

The students say it was obvious to them something unusual was happening and they wonder why the adults didn't act faster.

"I had to sit in the principal's office with the lights out and I was just crying in there," said Cannon.

More than 50 students went to hospitals for treatment. As for who should pay for all that medical care the district said parents should contact the central office so they can start working on that.