A mysterious oxygen tank encased in concrete at Southern Hills Middle School sparked a short-lived bomb scare for some summer-school students Thursday morning, but police ultimately concluded it wasn't a threat.
Boulder police officials said the compressed oxygen tank was first spotted around 7:40 a.m. by Boulder Valley School District maintenance crews who were chipping away at excess concrete on the ground on the school's east side.
Members of the Boulder County bomb squad were deployed to the school at 1500 Knox Drive, and a robot inspected the object, but was unable to remove it from the concrete, police said.
A human bomb technician wearing full protective gear approached the tank, removed it from the concrete and determined that it was not dangerous at around 10:20 a.m, police said.
Boulder police Sgt. Jeff Kessler said officials were initially concerned that if the tank contained oxygen and became uncapped, it could become a dangerous projectile.
The bottle was taken to the Boulder Fire Department for disposal, Kessler said, and students returned to the school shortly before 11 a.m.
Kessler said he does not know why the tank was embedded in the concrete, or when the excess concrete was poured.
"At this point, we don't have any investigative leads, so the case is closed," he said.
Kessler said police did not think there was imminent danger for people in the area at any point, but added that the maintenance crews who called about the tank did the right thing.
"The BVSD maintenance guys did a great job of looking at something, noticing it was out of the ordinary," Kessler said. "You don't usually chip away at concrete and find a bottle."
Two high school summer school classes were in session at the school at the time, said district spokeswoman Maela Moore.
A wellness class, with 48 students enrolled, was meeting inside the school and was moved to neighboring Fairview High as a precaution. Students returned to Southern Hills about 11 a.m.
An aerobic walking class, with 27 students enrolled, was outside well away from where the suspicious package, she said.
Moore said the district didn't alert parents when the incident first happened because "police had the situation under control." In an email sent around 2:30 p.m., summer school Principal Kady Haisley wrote that keeping students safe is a "top priority."
Kyra Hill, a ninth-grader in the wellness course, said her class was relocated to Fairview High for several activities Thursday morning, including basketball.
"It was a little freaky when we first came and saw the tape and the bomb squad," she said.
Hill said students knew there was nothing to worry about when they saw the bomb squad vehicle drive away.
Emily Gallegos, also in ninth grade, said she had noticed a mound of concrete near a wall on the east side of the school. She said students were told the concrete mound contained the oxygen tank.
The students said they were not instructed to call their parents.
"I don't think anybody was aware of the situation," Gallegos said.