Many students jumped out of windows during the shooting. Hissong told the Springfield News-Sun days after the shooting that improvements needed to be made to ensure students can get out of the building whenever they need to.
Right now, many windows at the school barely open.
"The windows will fully open with just the pull of one latch all the way out," Hissong said. "It will be easy to get out if necessary."
Screens that were covering the windows before the shooting have been removed, Hissong said, making escape easier. Also, film will be put over all exterior and interior windows to make it tougher for a window to break.
During the shooting, police said Serna fired into two classrooms through windows. A student, Adam Schultz, was hit by a pellet during the gunfire but was reportedly OK.
Along with the safety upgrades, school district officials are working to win a grant to hire long-term counselors. Experts who spoke with the Springfield News-Sun said effects from a school shooting can linger for months and years and it is important for the district to have resources for students' mental health.