"Everything is on schedule," said Principal Valerie Novak.
Holtzman said a North High employee doing a normal walk-through of the school before the students arrived this morning spotted an object in a locker that raised suspicion.
"As a precaution, police and fire marshals were called to the scene and contacted the employee," Holtzman said of the 7:20 a.m. call. "It was determined to be of no danger."
Deputy Superintendent Boyd Michael said authorities responded to a potential threat, but that as it turned out, the item never posed any threat.
By 8:30 a.m., Hagerstown City Police Lt. Richard Reynolds said the incident was over and the school was open.
"There are students trying to find their first classes," Reynolds said.
He said the police response to the incident was "appropriate to what was found" though he wouldn't say what, if anything, that was.
Mallory Crossland, a senior at North High, said the situation forced students to cancel the protest they'd planned to hold this morning over the school's new parking fee.
"We were supposed to have a parking protest, so we got up early, but they called that off because we can't get in the parking lot. A whole bunch of students were coming."
Instead, she said, they are now waiting in the McDonald's and another restaurant nearby for school to open.