University of Nevada, Reno and state of Nevada officials provided updates about a major explosion that caused significant damage to two dorms on July 5.

This is a breaking news story and will be updated.

What caused the explosion

A gas leak — caused by an initial, smaller explosion in one of the dormitory’s boilers — is what caused a large blast that substantially damaged the Argenta and Nye residence halls last Friday on the University of Nevada, Reno campus, State Fire Marshal Bart Chambers said at a Tuesday press conference.

The blast occurred as a third-party contractor was servicing Argenta’s No. 1 boiler, which has suffered mechanical issues earlier in the week and had been shut down, according to Chambers.

The initial blast severed a gas line in the building’s basement, where the boiler was located. The fire suppression system in the basement extinguished a small fire associated with that initial explosion, but natural gas continued to fill the basement — flowing into the air ducts and up the elevator shaft.

That gas later ignited, causing the second, larger blast. That explosion injured six students and two Reno firefighters.

Chambers could not say what ignited the gas.

Virginia Street is currently closed directly adjacent to Argenta and Nye halls as crews use a large crane to remove debris from the buildings.

UNR Chief of Police Todd Renwick said they are worried loose debris could blow off the buildings and onto campus or to nearby neighborhoods.

What is the status of Argenta's structural integrity?

The structural integrity of the building is sound, according to Vice Provost Kevin Carman. The pillars that support the building are in tact and are not expected to fall.

Why didn't the building catch fire?

The building did not catch fire after the explosion due to Argenta being a "well-designed fire retardant building designed not to catch fire," according to Renwick. Additionally, the fire sprinkler system is expected to have played a role in keeping the building from catching fire.

What will students planning to stay at Argenta, Nye hall do next school year?

Neither Argenta or Nye will be ready for students to move into when classes start in August, according to Shannon Ellis, vice president for student services.

She said the university is currently looking for 1,300 beds elsewhere in Reno for the students who would have moved into those dorms this fall. There's a possibility UNR could lease rooms with downtown Reno casino hotels.

Will the dorms be rebuilt?

UNR Provost Kevin Carman said the university plans to restore both buildings, a process that could take at least one — possibly two — years to complete.

“We can restore them, and we will restore them,” he said.

When will displaced students get their belongings back?

Renwick described reuniting students with their property as a "little bit more of an intense process" due to the wide variety of amount of items in each room. The university is prioritizing getting medications and passports out of rooms in Argenta.

"We have a priority list because we do have individuals who are leaving the country so we are trying to get their valuables," Renwick said.

What about the safety of other dorms?

Chambers said inspectors will look at every boiler and conduct fire safety inspections at all dorms at UNR as well as UNLV as a result of the July 5 explosion.

He said investigators believe the explosion on July 5 was an isolated incident and not a "global" problem.

When will Virginia Street reopen?

UNR police chief Todd Renwick said it should be business as usual along N. Virginia Street by next week.

WATCH: UNR gives updates on Argenta Dorm explosion

Timeline of events

Nevada Fire Marshal Bart Chambers said Tuesday the cause of the blast at Argenta Hall was because of a severed gas line, which was caused by a smaller boiler explosion.

Here is the general timeline of events of the explosion at UNR:

July 5:

Mid-day: Boiler technician arrives to repair and replace part on boiler, which had problems earlier in the week.

12:42-44 p.m.: Initial boiler explosion occurs.

12:44 p.m.: A gas line is severed.

12:44:45 p.m.: Alarm notifies people

12:45:11 p.m.: Fire pumps start running from fire sprinkler system. Evacuation begins.

12:45-47 p.m.: Initial fire was extinguished, but a free flow of natural gas from 3-inch pipe travels up elevator shaft.

12:51:51 p.m.: Reno Fire Department engine 4 dispatched to Argenta Hall.

12:56-57 p.m.: Technician shuts off main gas to Argenta Hall.

12:57:07 p.m.: RFD engine arrives

12:59 p.m.: RFD requests backup.

1:02 p.m.: Second major explosion occurs

1:02 p.m.: Third alarm requested, search and rescue operation begins

1:30 p.m.: Nevada Department of Public Safety dispatched. Witness interviews begins.

July 6

6:30 a.m. Investigators begin process of gathering evidence inside dorms.

5:30 p.m.: Investigators enter Argenta Hall. Plan was hatched to enter basement.

July 7

11:00 a.m.: Team enters basement, structural engineers have placed safety measures to get to origin of explosion.

5:40 p.m.: Investigators determine explosion was isolated incident.

4:00 p.m.: Nevada State Fire Marshal turns incident back to UNR.

President Johnson to be at press conference

UNR President Marc Johnson said he will be at the press conference today at 11 a.m.

Johnson was in Scotland when he was notified by his Chief of Staff Patricia Richard about what happened at Argenta Hall on July 5.

Richard said on a voicemail, "Call me immediately."

Johnson said UNR has an emergency management team that practices with drills. He said the experience in those mock disasters paid off.

Johnson said from Scotland he was on conference calls with the management team.

Johnson also said it was fortunate that no one was seriously injured when the explosion happened the day after a holiday and in the summer.

"Building can be repaired, people can't," he said.

He said UNR is currently working around the clock to figure out housing for students scheduled to move in residence halls next month.

This is a breaking news story and will be updated.

Siobhan McAndrew tells stories about the people of Northern Nevada and covers education in Washoe County. Read her journalism right here. Consider supporting her work by subscribing to the Reno Gazette Journal.