A “catastrophic failure” with a boiler in the basement of a UNR residence hall led to a massive explosion this summer, the Nevada Department of Public Safety concluded in an investigation made public Thursday that rules out a criminal motive or terror.

An explosion of the boiler occurred on July 5 during maintenance work. That blast caused damage to the basement of Argenta Hall and cut a natural gas line, which caused a fire and migrated from the basement into an elevator shaft and the first floor of the residence hall.

It ignited a second larger explosion that led to severe structural damage. The investigation, from the state fire marshal, could not determine what sparked the second explosion, though the report speculates that possibilities ranged from cooking equipment to elevator cars.

“We have anxiously been awaiting this report and can now better understand the events that led up to this unprecedented event,” UNR President Marc Johnson said in a statement. “We are very fortunate and grateful that while there were minor injuries, there were no fatalities, and the explosion was not criminal or terror related.”

The blasts left eight students with minor injuries, according to the university. An investigative document, included with the report’s release, described a survey the day after the explosions that found blown-out windows in Argenta Hall and Nye Hall, as well as significant structural damage.

“The entire north back wall of Argenta was almost completely blown out from the middle of the building between the residence halls,” the document said. “The wall was destroyed exposing insulation and bent metal up the entire height of the building.”

The buildings have been closed since the incident. In July, the university said it expected Argenta Hall to reopen in the fall of 2021, while Nye Hall is slated to re-open by Fall 2020.

Regents were scheduled to hear an update on the situation during their Friday meeting from Shannon Ellis, vice president of student services. 

About 1,300 displaced students are being housed in the Sky Tower at Circus Circus, which is five blocks from campus and has been rebranded “Wolf Pack Tower.” Amador Stage Lines is providing shuttle service on a 7-minute loop throughout the day.

The tower has 196 single rooms with a king-size bed and more than 600 double occupancy rooms with two queen-size beds. Rooms also include large TVs, mini refrigerators, a private bathroom, desks and a dresser. 

Students are being charged the rate they would have paid for Argenta and Nye halls, which is $5,800 for nine months. The tower, which does not feature gambling, is only available to university students and not the general public. 

More academic support staff have been hired to provide mentorship and tutoring in a study area established in what used to be a wedding chapel. A UNR police substation has been established in the tower, and the ratios of resident assistants to students is higher in the tower than in on-campus residence halls. 

Dining service — disrupted because the Downunder Cafe in Argenta Hall was caught in the blast — is currently being provided by a modular kitchen and four tents that seat about 300 students, as well as at the Overlook Cafe. 

Meals eventually will be provided at a 17,000-square-foot semi-permanent dining facility. The modular structure seats about 480 people, includes heating and air conditioning and has a translucent ceiling to allow light into the space.