By GARY B. TINAGERO and PHILIP LUNA
Sandia National Laboratories (SNL) is a multimission laboratory located in Albuquerque, New Mexico, and is one of three National Nuclear Security Administration research and development laboratories located in the United States. Recently, SNL’s Emergency Response Team (ERT) responded to an incident involving a sulfur dioxide (SO2) fixed monitor, setting off the alarm inside a laboratory and in the adjacent hallway. The potential sources for the alarm were various experiments involving batteries and an uninterrupted power supply (UPS) in the immediate area.
The responders were dispatched to “Building XYZ” in “Room 123” (the actual building and room number have been changed for this article). The response consisted of an incident commander (IC), a support officer, and ERT members.
The building was a large, single-story structure consisting of Type II construction and housing numerous individual laboratories that were occupied. However, construction was being done to the interior and exterior of the building. The monitor initiating the alarm had no prior history of malfunction, and the unit had been beeping since 0700 hours. The only known process being conducted in the building at the time was an experiment under a vent hood. Fumes generated from the experiment should have been captured by the ventilation system and scrubbed before being released to the atmosphere. Portable meters showed no readings outside of the room and provided no confirmation of a SO2 hazard. Lab personnel exited the building and met with the IC on his arrival.
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Initial Actions
The first-arriving unit was Response 1, who conducted a 360° size-up of the building’s exterior conditions for incoming units and assumed command in the offensive strategy/investigative mode. Command was designated as “XYZ Command.” The IC interviewed the technicians from the affected lab who were waiting outside the building and requested additional resources to include the building manager and safety subject matter experts (SMEs). As other units arrived, an incident command post was established in the street at the nearest intersection and an isolation perimeter was established around the building. The construction area was evacuated to include workers on the roof. All lab workers and personnel in the hall around the labs were evacuated.
(1) The SNL incident command post. (Photos courtesy of the SNL Emergency Response Team.)
The lab owner was then interviewed to identify the processes currently being conducted inside the lab. Based on the known and confirmed information, it was theorized that a sensor in the room could have caused the alarm. As the incident progressed, the entire building was evacuated using the mass communications system, and the fire alarm was activated.
Initial Incident Action Plan (IAP)
The initial IAP included conducting medical monitoring of the ERT, donning of protective ensembles, and provisioning of monitoring inside the structure. It also included ensuring the members of the workforce in the immediate area had evacuated. Command then moved incident communications from the primary emergency management channel to “Tac Channel 1.” The entry team was assigned to “Tac Channel 2” for direct communications with the hazmat response team (HMRT) supervisor. The ERT and backup team donned Level B (i.e., chemical splash) protective clothing with self-contained breathing apparatus (SCBA) for respiratory protection. Personnel then entered the building to conduct reconnaissance and begin portable monitoring operations.
The ERT made entry into the structure through the lobby and into the hallway. Initial portable monitors read 0.2 parts per million (ppm) SO2 in hallway. As the ERT reached the lab in question, they noted the exterior lab monitor display was in alarm. The ERT’s portable monitors were now reading 0.4 ppm SO2 at the lab door. As the ERT entered the laboratory, initial readings were now logged as 0.7 ppm; readings were constant at 0.9 ppm SO2 as personnel moved across the laboratory. The ERT then propped opened an exit door on the east side to increase ventilation.
The ERT conducted a thorough search for personnel in the rest of building and found no one present. The building was declared “all clear” of occupants, and the ERT exited.
The support officer then plotted the air monitor results and analyzed the situation. Based on this analysis, the ERT was sent to rehab to follow up on medical monitoring, nourishment, and hydration, and the HMRT reassessed the situation. The command team communicated essential elements and tasks to the team for the next entry operation.
IAP: Second Entry Operation
The second entry focused on several critical tasks, including the need to continue monitoring in the lab area and focus on the areas that produced the SO2 readings. The ERT’s focus was on the batteries used in the various experiments and the UPS inside the lab. Additionally, the ERT ruled out all other gases in the area including methane and hydrogen sulfide (H2S). Command contacted the heating, ventilation, and air-conditioning facilities representative and requested that building ventilation be increased to provide 100% outside air.
(2) The SNL incident commander and support officer.
After being briefed, the ERT members made entry into the hallway, where SO2 readings had increased to 0.4 ppm. The ERT then moved into the lab where the readings had also increased slightly to 0.8 ppm SO2. Prior to making entry, the lab SME instructed the ERT to shut down active experiments using the lab computer.
The ERT portable monitor low-level alarm then activated because of an apparent increase of SO2 to 12 ppm. Command immediately requested a CAN (Conditions, Actions, Needs) report from the ERT, and their status was relayed back to command. The lowest SCBA air pressure was noted at 2,000 pounds per square inch; the ERT had performed four program shutdowns and observed that there was a power spike with the UPS. There were no additional needs. The ERT completed their assigned tasks and then exited the lab. The south hallway reading was 0.6 ppm SO2 as they exited the building and went off air.
IAP: Third Entry Operation
Tactical objectives for the third entry operation were to remove the SO2 sources. The ERT focused on the battery experiments and the UPS, which had some bulging batteries and elevated levels of SO2 in the immediate area. The ERT was then instructed on how to safely remove the UPS if necessary, depending on monitor readings, and transport it to an outside location where the battery off-gassing would be less of a hazard.
The ERT entered the structure for its third entry operation. As discussed, they monitored the experiment areas and UPS, where they found a reading of 0.1 ppm SO2. The UPS readings were still elevated, and the decision was made to remove the UPS to the loading dock; it was then electrically disconnected and removed from the building. To continue their systematic search for the SO2 source, the ERT monitored the adjacent labs/rooms without recording elevated readings. The ERT conducted follow-up readings in the lab area after the sources were removed. There was no change indicated, as the SO2 levels remained elevated. The ERT exited the building, went off air, and reported to rehab.
Command then requested that the SME obtain data from the remote heat monitors in the building to identify any heat anomalies. These readings indicated that two rooms in the construction area had elevated temperatures and were inconsistent with other areas. These areas would be a target for the next entry operation.
(3) The SNL Emergency Response Team.
IAP: Fourth Entry Operation
Given that all known sources of SO2 had been eliminated from the lab and the building, a “safety pause” was conducted. There was an extensive consultation between the command team and the SMEs on scene as well as the various facility teams, which were assembled in the Emergency Operations Center. After a lengthy deliberation, the IAP shifted to conduct a systematic room-to-room monitoring of the entire building.
The ERT reentered the building with portable monitors indicating 0.8 ppm SO2 in Lab Room 123. The readings continued to climb as the team searched and monitored each individual lab down the hallway from the original site of the alarm. Readings were not significant and fluctuated between 1.2 and 1.4 ppm SO2. Command requested an additional CAN report. The ERT reported their monitoring progress, checked their SCBA air supply, and reported no unmet needs.
The ERT entered the construction area, and the two rooms earlier identified with significant temperature differences continued to show significant SO2 readings of 12.0 and 19.0 ppm. The ERT reported the presence of construction equipment to include a torch kit with an acetylene tank in the room. The photoionization detector (PID) indicated the lower explosive limit (LEL) was achieved by reading 19%. This potentially indicated that the tank or another unknown flammable gas source was present and leaking. The ERT checked the acetylene tank and found the valve was in the open position; the valve was then quickly secured. The torch wand valve was also found to be in the open position and then closed.
(4) The incident’s rehab and hydration area.
These findings were relayed to command, and the ERT was then ordered to exit the structure because of the flammable atmosphere. The ERT exited the building, went off air, and reported back to rehab for hydration and nourishment.
IAP: Fifth Entry Operation
The SNL IC requested fire support because of the flammable/explosive atmosphere indicated by the PID. The air force base fire department responded under the command of a battalion chief. Medical support was also requested. The battalion chief was briefed on the situation and joined the SNL command team as part of the unified command. Engine crews deployed handlines to ensure the safety of the next entry team. The ERT changed their personal protective equipment to structural firefighting clothing and SCBA for potential flammable atmosphere protection. A rapid intervention team was also established.
The ERT then reentered the structure for follow-up monitoring. The SO2 readings had dissipated rapidly in all areas because of the increased ventilation. The ERT exited the building, went off air, and reported to rehab. At this point, the building was declared “fire safe” and sealed for further monitoring.
Concerns and Issues
The SMEs researched case studies regarding conversion factors for SO2 and acetylene. They determined that acetylene can mimic SO2. Technically known as “electrochemical cross interference,” it was found that all the ceiling tiles in the construction area had been removed, which allowed acetylene vapors to travel throughout the building through the void space above the ceiling. The vapor density for SO2 is 2.25 and for acetylene is 0.907 (air is 1.0). The LEL in the construction area where the acetylene was located had reached up to 19%, with no LEL outside of the rooms.
The SNL command team also considered if it was possible for methane or H2S sewer gas in P-traps to cause false readings or if it was because of other work being conducted in the construction area. This was ruled out; the increase of 100% outside air flow into Building XYZ did not decrease the SO2 readings in Room 123 and adjacent areas.
Termination and Recovery Activities
Termination and recovery standard operating proceduress were used with various activities and interactions. After a complete survey and monitoring of the building, it was deemed that no hazards were present. An investigation was completed on the acetylene tank and torch parts and found there were no defects noted. The acetylene tank was then removed to a safe area outside of the building.
It was determined by SNL SMEs that the hazard was completely mitigated and the building was safe to be reoccupied. The acetylene bottle was removed, and normal operations were reestablished in Building XYZ.
Beware the “Rabbit Hole”
The SNL command team’s initial IAP was based on on-scene cues and incident clues. The presence of the acetylene cylinder and the operator turning on the cylinder was conveyed to the SMEs by the operator. This information was relayed to command early in the incident (the operator had not checked or commented if torch wand valves were off). Additionally, the lab owner stated there were bulging batteries inside the lab; this was confirmed later by the ERT. Lab technicians indicated that the batteries had a history of producing elevated SO2 readings.
All known and confirmed information pointed to the batteries—until they were eliminated from the equation. The fixed monitor’s alarms and the portable monitor’s readings for SO2 were the “rabbit hole” that drove the IAP. Fortunately, the command team and ERT members found the true source of the elevated readings, and the SMEs confirmed through their diligent research that other sources can cause erroneous readings. Electrochemical cross interference is very real!
Operational Strengths
A strong incident command system (ICS) and incident analysis process was maintained throughout numerous entry operations. Hazmat procedures were followed, leading to a successful outcome. A team effort was responsible for the successful outcome and involved numerous responders, SMEs, and safety personnel. A strategic, safe, and successful operation was carried out over the course of several hours and is a testament to the ICS and tactical training operations of the American fire service.
Authors’ note: This article is dedicated to Mike Collado (1960-2021), this response’s incident commander as well as a 9/11 Pentagon attack responder and member of the Albuquerque (NM) Fire Department.
GARY B. TINAGERO, MS, EFO, CFO, has been a member of the Sandia National Laboratories (SNL) Emergency Response Team since 2018 and is emergency management’s program coordinator for the Sandia Agency Representatives and the Duty Officers. Prior to joining SNL, Tinagero served 27 years with the Albuquerque (NM) Fire Department, retiring as a battalion commander. He has also been a contributor to Fire Engineering.
PHILIP LUNA has been a member of the Sandia National Laboratories (SNL) Emergency Response Team (ERT) for six years. He also served as the ERT’s hazmat coordinator with responsibilities that included subject matter expert and conducting training, drill planning, equipment maintenance, and records management. Luna is also a Sandia Agency Representative (SAR), the SNL’s liaison for emergency response with Kirtland Fire and Emergency Services. Prior to joining SNL, he retired as a captain from the Albuquerque (NM) Fire Department. Luna is a 26-year veteran of the emergency response and fire services, with 23 of those years including hazardous materials response. He has certifications as a confined space and rope rescue technician, a hazmat technician, and an emergency medical technician—EMT-B in New Mexico, Nevada, and the National Registry.
