Campus Alert Archive
UC Riverside

Transient Opens Nitrogen Tank Valves in UCR Chemistry Lab at 7 AM, Triggering Hazmat Evacuation and Arrest

CAhazmatadvisorymedium confidence
Confirmed Threat

Shortly before 7:15 AM PST on Thursday, December 9, 2021, an unhoused woman accessed a laboratory in UC Riverside's Chemical Sciences Building near North Campus Drive and Big Springs Road and opened the valves on multiple nitrogen gas containers. Witnesses called 911; UCR police arrived within moments and took the woman into custody without incident. The Riverside Fire Department Hazmat team responded with four engine crews and two truck companies to monitor oxygen levels and stop the gas release; the building was evacuated and no one was injured.

Alerts
3
Response
—
Killed
—
Injured
—
Institution
University of California, Riverside
Public R1 · CA
~26,000 studentsUCR Alert
Confirmed Timeline

Alert Sequence

3 messages in sequence

Some alert texts below are approximate reconstructions from news coverage, not confirmed verbatim transcripts. Reconstructed texts are shown in italic with a dashed border. Verified verbatim texts have a solid border and are marked accordingly.

INITIAL ALERTSMS
Approximate reconstruction251 chars
UCR Alert: The Chemical Sciences Building is being evacuated due to a hazmat situation involving opened nitrogen gas containers. UCR Police are on scene. Avoid the area near North Campus Drive and Big Springs Road. Riverside Fire Hazmat is responding.

This text has been reconstructed from news coverage and may not reflect the exact original wording.

The activity was reported at approximately 7:15 AM PST; at that hour the building likely had few occupants, which minimized potential exposure risk
The Chemical Sciences Building at UCR is located at the intersection of North Campus Drive and Big Springs Road, in the science quad on the east side of campus
The woman opened valves on nitrogen containers in a laboratory; compressed nitrogen is not immediately toxic but displaces oxygen rapidly in an enclosed space, creating an asphyxiation hazard
UPDATESMS
Approximate reconstruction304 chars
UCR Alert Update: A suspect has been taken into custody. Riverside Fire Hazmat teams are inside the Chemical Sciences Building monitoring oxygen levels and stopping the gas release. The building remains evacuated. There are no injuries. We will provide an all-clear when the building is safe to re-enter.

This text has been reconstructed from news coverage and may not reflect the exact original wording.

UCR Police took the woman into custody before Riverside Fire Department arrived; the custody was accomplished without incident, suggesting the woman did not resist and may not have been aware of the hazard she created
The four engine crews and two truck companies deployed reflects Riverside Fire's standard tiered response for a Class B hazmat incident in an occupied laboratory building
Nitrogen gas monitoring is the key response action: nitrogen displaces oxygen silently and without warning signs like odor, making entry-team oxygen monitoring essential before releasing the all-clear
ALL CLEARSMS
Approximate reconstruction220 chars
UCR Alert: The Chemical Sciences Building has been cleared by Riverside Fire Hazmat. Oxygen levels are normal and the building is safe to re-enter. The nitrogen gas release has been stopped. Normal operations may resume.

This text has been reconstructed from news coverage and may not reflect the exact original wording.

The all-clear was issued the same morning, indicating the nitrogen purged from the enclosed spaces relatively quickly once the valves were closed and ventilation restored
The Patch coverage notes the hazard was 'quickly mitigated,' suggesting total hazmat operational time was under two hours
Context

Background

The University of California, Riverside's Chemical Sciences Building is a primary research and teaching facility for the Department of Chemistry, located in the science complex near North Campus Drive and Big Springs Road. The building houses compressed gas cylinders including liquid nitrogen, nitrogen gas, and other research gases as standard laboratory equipment. On December 9, 2021, an unhoused woman gained access to the building at approximately 7:15 AM PST and entered a laboratory where she allegedly opened valves on nitrogen gas containers. MyNewsLA reported that witnesses called 911 and UCR Police arrived within moments, taking the woman into custody without incident before Riverside Fire Department arrived. Banning-Beaumont Patch reported that the Riverside Fire Department Hazmat team deployed entry teams to monitor oxygen levels and stop the release, with four engine crews and two truck companies responding. The building was evacuated; no injuries occurred. The incident raises a campus security challenge at research universities: laboratory buildings often have multiple access points and are difficult to fully secure, especially at early morning hours before regular building monitors arrive. Nitrogen gas incidents at laboratory facilities carry an underappreciated asphyxiation risk because nitrogen is colorless, odorless, and tasteless, providing no sensory warning of oxygen displacement.
Analysis

Key Findings

The incident illustrates a campus security vulnerability at research universities: laboratory buildings housing hazardous materials are frequently accessible to non-campus individuals during off-hours, and compressed gas cylinders pose an asphyxiation hazard when valves are opened indiscriminately
UCR Police's rapid response -- taking the suspect into custody before Riverside Fire arrived -- prevented any escalation and enabled the hazmat team to focus on gas containment and oxygen monitoring rather than suspect management
The early morning timing (7:15 AM) when building occupancy was minimal significantly reduced potential exposure risk, a fortuitous factor that should not be relied upon as a mitigation strategy
Outcome
Homeless woman arrested without incident. No injuries. Riverside Fire Department Hazmat team contained the nitrogen release and monitored oxygen levels. Building cleared and reopened.
Provenance

Sources

  1. News
    Woman Allegedly Opens Nitro Containers at UCR, Prompting Emergency Response (MyNewsLA, December 9, 2021)
    mynewsla.com
  2. News
    Details Released In HazMat Incident At UC Riverside (Banning-Beaumont Patch)
    patch.com
Tags
nitrogen-gashazmatchemical-sciences-buildingcompressed-gasunhoused-persontrespassasphyxiation-hazardriversidecaliforniapublic-r1no-injuries
Added May 2026Updated May 2026Via ingestion