A gas leak, an explosion or just an experiment gone wrong?

USC students received a puzzling email from the Department of Public Safety on Thursday about a gas leak at the Neely Petroleum Engineering Building that sent one person to the hospital due to an injury sustained from the incident. Between conflicting accounts from USC Viterbi Dean Yannis C. Yorstos and DPS Chief David Carlisle, students are still confused about what exactly happened at the building.

The incident occurred shortly before 4 p.m. DPS Chief Carlisle confirmed the explosion, while Dean Yortsos said it was not an explosion, just a science experiment gone wrong. Seven fire trucks, three paramedic ambulances, two battalion command vehicles and a hazmat vehicle responded to the scene.

According to Yortsos, a student was performing an experiment with nitrogen gas before it became pressurized and the container exploded. The student was transported to the hospital following the incident.

"He was stunned, but he was able to walk out on his own," said Yortsos. "And then he went to hospital just to make sure that nothing else was wrong, and he was released. And actually, he was back in the lab the next day."

Evacuations of Neely and the surrounding four buildings were inexplicably delayed for a few minutes while DPS and the Los Angeles Fire Department gathered information on the incident.

Thirty minutes after the purported leak occurred, the USC community was notified via an email from DPS. Sent to all students and staff, the TrojansAlert emergency notification system detailed the gas incident after including an unfilled template DPS uses to deliver incident details.

"It was just really weird, for a situation like that you’d expect them to have it right," said USC sophomore Leonel Herrera.

Spencer St. Denis, a senior at USC, was at the USC-UCLA basketball game when he received the notifications from DPS.

"It was kind of weird to see that because USC has so many credible people and staff, and then to have that happen, you go, ‘What really was going on there?’ Like, was this kind of something that could have been prevented?" St. Denis said.

This is not the first time USC students have received confusing information from DPS.

"I’ve seen a templated email, and then two emails later I see the correct email they intended to send," said Herrera.

According to CBS L.A., this is the fourth time LAFD has responded to a hazmat emergency at USC since September and the second time they responded to this specific building

While DPS had alerted the USC community of the gas leak via Twitter and TrojansAlert, LAFD did not initially confirm the report. A hazmat team eventually evaluated the building and found no leaks or fires, and the building was promptly reopened.

A press release from LAFD read, "LAFD Hazardous Materials Squad made entry and checked every floor in the building. They found no hazards and confirmed there were no leaks. All air readings (via handheld gas meter) were normal. Only the initial patient (as per first alert) was transported, there were no other injuries reported. Most LAFD resources will be released while one task force remains to oversee the repopulation of the building."

In response to criticism of the confusing message, Carlisle said that DPS has a short period of time to assess the dynamic situation, and safety is their primary concern.

Herrera noted that DPS should improve its alert system so as to further ensure the safety of the community: "With a situation of that gravity, it should be done right the first time rather than confuse students."