The discovery of a small amount of mercury Wednesday morning at Walter Johnson Junior High created what Las Vegas Fire and Rescue Public Information Officer Tim Szymanski calls, "The largest decontamination incident ever in the history of our department."
It was just the amount of mercury you might find in an old-school thermometer that caused the huge response, leaving many asking, was it overkill? Was the district prepared?
And one thing big on parents' minds, did they communicate properly?
Contact 13 has been digging for answers.
Listening to the parents hurling curses -- some stuck for more than 12 hours overnight waiting for their children -- you'd say a lot was wrong with the way Clark County School District handled this event.
CCSD police say it was not a hoax and not a terrorist threat.
"At this point it appears it was kids being kids, playing with a substance," said CCSD Police Capt. Ken Young.
No students were hurt. None got sick, needed treatment or transport for medical care.
But two parents waiting outside did need medical attention -- not because of mercury exposure.
"This is probably, I would say, the longest incident that we've had," Young said.
Las Vegas Fire and Rescue had 25 pieces of equipment and 80 firefighters on scene, but it still wasn't enough to screen almost 1,300 people.
"We had to go as far as San Francisco to get more EPA resources to come in," Young said.
So is the district prepared for a true mass emergency?
"I think overall we are prepared. The process is the process," said Young. "I don't think you could have made that any faster."
But parents tell 13 Action News there was a communication breakdown. Too much waiting around and too little information.
"One of the big concerns was getting active communication out," said Young.
The district relied on their automated Parentlink information system and the media to get word out about what was happening.
On the scene, Young said, "We used our PA systems on our vehicles. We used the PA systems on the buses. So we improvised last night."
Improvisation that left many parents in the dark about just how long they'd be waiting for their kids.
What did the district tell parents -- here's how many kids, here's how many screeners and here's how long each kid will take?
"I couldn't give them estimates on how long it would take because we ran into some complications where kids had higher levels of readings on them, there were further screenings on those kids," Young said.
And the EPA says, further decontamination from wiping kids down, to putting them in showers to washing their hair and blowing it dry because mercury vaporizes with heat.
"So you couldn't give a hard number to say that it's going to take two hours, it's going to take three, we really could not give them that information."
We asked the district how it felt the incident was handled.
"Once we do the final assessment, we'll give a grade," said Young. "But yeah, communication could always be better. On both ends."
The district is still investigating who brought the mercury, where they got it, exactly how much there was, and whether they'll take any disciplinary action.