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Home My WebLink AboutExposition Fire Report_RedactedNFIRS-1 Basic 40060 CA 08 28 2025 Fire Station 1 (FS1) 25-05059 0 FDID State Month Day Year Station Number Exposure Location Type Census tract: Street Address Intersection In Front Of Rear Of Adjacent To Directions US National Grid 2220 EXPOSITION # Number Prefix Street or Highway Street Type Suffix San Luis Obispo CA 93401 Apt./Suite/Room City State Zip Code Cross Street Incident Type 111-Structure Fire Aid Given Or Received 1 Mutual Aid Received 2 Auto. Aid Received 3 Mutual Aid Given 4 Auto. Aid Given 5 Other Aid Given None CALFIRE (40080) Their FDID Their State Their Incident Number Dates and Times Alarm 08 28 2025 07:04 Arrival 08 28 2025 07:09 Controlled 08 28 2025 07:22 Last Unit Cleared 08 28 2025 10:46 Shifts and Alarms C 1 FZ1 Shift or Platoon Alarms District Special Studies 9244 3 - No, COVID 19 was not a factor ID# Value Actions Taken 10-Fire control or extinguishment, other Primary Action Taken Resources Apparatus or Personnel Module is used. Apparatus Personnel Suppression 7 16 EMS 0 0 Other 1 1 Resource counts include aid received resources. Estimated Dollar Losses and Values Losses:Required for all fires if known. Optional for all non-fires. None Property:$ 25,553.00 Contents:$ 76,659.00 Pre-Incident Values: Optional None Property:$ 127,765.00 Contents:$ 95,824.00 A B C D E1 E2 E3 F G1 G2 Page 1 of 16 Completed Modules 2 - Fire 3 - Structure Fire 4 - Civilian Fire Cas. 5 - Fire Service Cas. 6 - EMS 7 - HazMat 8 - Wildland Fire 9 - Apparatus 10 - Personnel 11 - Arson Casualties None Deaths Injuries Fire Service 0 0 Civilian 0 0 Detector Required for Confined Fires 1 - Detector Alerted Occupants 2 - Detector Did Not Alert Them 3 - Unknown Hazardous Materials Release 1 - Natural Gas 2 - Propane Gas 3 - Gasoline 4 - Kerosene 5 - Diesel Fuel / Fuel Oil 6 - Household Solvents 7 - Motor Oil 8 - Paint 0 - Other None Mixed Use Property Not Mixed 10 - Assembly Use 20 - Education Use 33 - Medical Use 40 - Residential Use 51 - Row Of Stores 53 - Enclosed Mall 58 - Business and Residential 59 - Office Use 60 - Industrial Use 63 - Military Use 65 - Farm Use 00 - Other Mixed Use Property Use None Structures 131 Church, Place of Worship 161 Restaurant or Cafeteria 162 Bar/Tavern or Nightclub 213 Elementary School, Kindegarten 215 High School, Junior High 241 College, Adult Education 311 Nursing Home 331 Hospital 341 Clinic, Clinic-Type Infirmary 342 Doctor/Dentist Office 361 Prison or Jail, Not Juvenile 419 1- or 2-Family Dwelling 429 MultiFamily Dwelling 439 Rooming/Boarding House 449 Commerical Hotel or Motel 459 Residential, Board and Care 464 Dormitory/Barracks 519 Food and Beverage Sales 539 Household Goods, Sales, Repairs 571 Gas or Service Station 579 Motor Vehicle/Boat Sales/Repairs 599 Business Office 615 Electric-Generating Plant 629 Laboratory/Science Laboratory 700 Manufacturing Plant 819 Livestock/Poultry Storage (Barn) 882 Non-Residential Parking Garage 891 Warehouse Outside 124 Playground or Park 655 Crops or Orchard 669 Forest (Timberland) 807 Outdoor Storage Area 919 Dump or Sanitary Landfill 931 Open Land or Field 936 Vacant Lot 938 Graded/Cared for Plot of Land 946 Lake, River, Stream 951 Railroad Right-of-Way 960 Other Street 961 Highway/Divided Highway 962 Residential Street/Driveway 981 Construction Site 984 Industrial Plant Yard Property Use: Description Look up and enter a Property Use code and description only if you have NOT checked a Property Use box. Owner Local Option Person/Entity Type Business Name (if applicable) Phone Number Mr., Ms., Mrs.First Name MI Last Name Suffix Number Prefix Street or Highway Street Type Suffix Post Office Box Apt./Suite/Room City State Zip Code Remarks: BC 2 dispatched to the above location for a report of a structure fire with smoke and a fire reported by RP. BC 2 arrived on the scene and took over IC from T1. RP reported that everyone was out of the structure. Units at the scene were given assignments and conducted a fire attack and primary search. E3 found a lithium-ion battery in the area of origin. The FM arrived at the scene and was assigned safety. Once the fire was extinguished, the FM requested that we make contact with the Co. Haz Mat team. Prevention officer 22 arrived at the scene and worked with the two on-duty Haz Mat personnel to make contact with HM 1. Due to the smoke produced by the battery, HM 1 was asked to respond. HM1 and Prev. 22, along with the other HM personnel, worked to monitor and provide gas monitoring of the structure. Once the battery was properly secured and the home was found to be clear of hazardous conditions, all crews did a grouse decon at the scene, and the incident was then TOT BC 1 and BC 2 cleared. Please see additional narratives for further details. H1 H2 H3 I J K2 L Page 2 of 16 Authorization 62800 MacDonald, John 08/28/2025 Officer In Charge ID Signature Position or Rank Assignment Date 62800 MacDonald, John 08/28/2025 Member Making Report ID Signature Position or Rank Assignment Date M Page 3 of 16 NFIRS-2 Fire 40060 CA 08 28 2025 Fire Station 1 (FS1) 25-05059 0 FDID State Month Day Year Station Number Exposure Property Details B1 1 Not Residential Estimated number of residential living units in the building of origin whether or not all units became involved B2 Buildings Not Involved Number of buildings involved B3 None Less than 1 acre Acres burned (outside fires) On-Site Materials Or Products On-Site Materials Storage Use Ignition D1 14-Common room, den, family room, living room, lounge Area of Fire Origin D2 10-Heat from powered equipment, other Heat Source D3 14-Floor covering or rug/carpet/mat, surface Item First Ignited D4 41-Plastic Type of Material First Ignited Cause of Ignition 1 - Intentional 2 - Unintentional 3 - Failure of Equipment or Heat Source 4 - Act of Nature 5 - Cause Under Investigation U - Cause Undetermined After Investigation Factors Contributing to Ignition 20-Mechanical failure, malfunction, other Factor Contributing to Ignition 30-Electrical failure, malfunction, other Factor Contributing to Ignition Human Factors Contributing to Ignition Check all applicable boxes None 1 - Asleep 2 - Possibly impaired by alcohol or drugs 3 - Unattended person 4 - Possibly Mentally Disabled 5 - Physically Disabled 6 - Multiple Persons Involved 7 - Age Was A Factor Estimated Age of Person Involved Male Female Equipment Involved In Ignition Equipment Involved Brand Model Serial # Year Equipment Power Source Equipment Power Source Equipment Portability 1 - Portable 2 - Stationary Portable equipment normally can be moved by one or two persons. Fire Suppression Factors A B C D E1 E2 E3 F1 F2 F3 G Page 4 of 16 Mobile Property Involved 1 - Not involved in ignition, but burned 2 - Involved in ignition, but did not burn 3 - Involved in ignition and burned None Mobile Property Type and Make Mobile Property Type Mobile Property Make Local Use Pre-Fire Plan Available Arson Report Attached Police Report Attached Coroner Report Attached Other Reports Attached Mobile Property Model Year State License Plate Number VIN _________________________ _________________________ _________________________ _________________________ _________________________ _________________________ H1 H2 Page 5 of 16 NFIRS-3 Structure Fire Structure Type 1 - Enclosed Building 2 - Portable/Mobile Structure 3 - Open Structure 4 - Air-Supported Structure 5 - Tent 6 - Open Platform 7 - Underground Structure 8 - Connective Structure 0 - Other Building Status 1 - Under Construction 2 - In Normal Use 3 - Idle, Not Routinely Used 4 - Under Major Renovation 5 - Vacant and Secured 6 - Vacant and Unsecured 7 - Being Demolished 0 - Other U - Undetermined Building Height 2 Number of Stories At/Above Grade 0 Number of Stories Below Grade Main Floor Size 700 Total Square Feet OR BY Length (ft) X Width (ft) Fire Origin 1 Below Grade Story of Fire Origin Fire Spread Confined to Object of Origin 2 - Confined to Room of Origin 3 - Confined to Floor of Origin 4 - Confined to Building of Origin 5 - Beyond Building of Origin Number of Stories Damaged By Flame Number of Stories w/Minor Damage (1-24%) Number of Stories w/Significant Damage (25-49%) Number of Stories w/Heavy Damage (50-74%) Number of Stories w/Extreme Damage (75-100%) *Count the roof as part of the highest story Type of Material Contributing Most to Flame Spread K1 Item Contributing Most to Flame Spread K2 Type of Material Contributing Most To Flame Spread Presence of Detectors N - None Present 1 - Present U - Undetermined Detector Type 1 - Smoke 2 - Heat 3 - Combination of Smoke and Heat 4 - Sprinkler, Water Flow Detection 5 - More Than One Type Present 0 - Other U - Undetermined Detector Power Supply 1 - Battery Only 2 - Hardwire Only 3 - Plug-In 4 - Hardwire With Battery 5 - Plug-In With Battery 6 - Mechanical 7 - Multiple Detectors & Power Supplies 0 - Other U - Undetermined Detector Operation 1 - Fire Too Small To Activate 2 - Operated 3 - Failed To Operate U - Undetermined Detector Effectiveness 1 - Alerted Occupants, Occupants Responded 2 - Alerted Occupants, Occupants Failed to Respond 3 - There Were No Occupants 4 - Failed to Alert Occupants U - Undetermined Detector Failure Reason 1 - Power Failure, Shutoff, or Disconnect 2 - Improper Installation or Placement 3 - Defective 4 - Lack of Maintenance, Dirty 5 - Battery Missing or Disconnected 6 - Battery Discharged or Dead 0 - Other U - Undetermined I1 I2 I3 I4 J1 J2 J3 K L1 L2 L3 L4 L5 L6 Page 6 of 16 Presence of Automatic Extinguishing System N - None Present 1 - Present 2 - Partial System Present U - Undetermined Type of Automatic Extinguishing System 1 - Wet-Pipe Sprinkler 2 - Dry-Pipe Sprinkler 3 - Other Sprinkler System 4 - Dry Chemical System 5 - Foam System 6 - Halogen-Type System 7 - Carbon Dioxide System 0 - Other U - Undetermined Required if fire was within designed range of AES Operation of Automatic Extinguishing System 1 - Operated/Effective 2 - Operated/Not Effective 3 - Fire Too Small To Activate 4 - Failed To Operate 0 - Other U - Undetermined Required if fire was within designed range Number of Sprinkler Heads Operating 1 Required if system operated Reason for Automatic Extinguishing System Failure 1 - System Shut Off 2 - Not Enough Agent Discharged 3 - Agent Discharged But Did Not Reach Fire 4 - Wrong Type of System 5 - Fire Not In Area Protected 6 - System Components Damaged 7 - Lack of Maintenance 8 - Manual Intervention 0 - Other U - Undetermined Required if system failed or not effective M1 M2 M3 M4 M5 Page 7 of 16 NFIRS-9 Apparatus or Resources 40060 CA 08 28 2025 Fire Station 1 (FS1) 25-05059 0 FDID State Month Day Year Station Number Exposure B Apparatus/Resource Dates/Times Sent Number of People Apparatus Use Actions Taken ID:BC2 Type:92-Chief officer car Dispatch:08/28/2025 07:04 Arrival:08/28/2025 07:09 Clear:08/28/2025 10:46 Sent 1 Suppression EMS Other 81-Incident command ID:CHIEF2 Type:92-Chief officer car Dispatch: Arrival:08/28/2025 07:15 Clear: Sent 1 Suppression EMS Other 55-Establish safe area ID:E2 Type:11-Engine Dispatch:08/28/2025 07:04 Arrival:08/28/2025 07:21 Clear:08/28/2025 07:47 Sent 3 Suppression EMS Other 12-Salvage & overhaul ID:E3 Type:11-Engine Dispatch:08/28/2025 07:04 Arrival:08/28/2025 07:10 Clear: Sent 3 Suppression EMS Other 10-Fire control or extinguishment, other ID:E4 Type:11-Engine Dispatch:08/28/2025 07:04 Arrival:08/28/2025 07:09 Clear:08/28/2025 09:13 Sent 3 Suppression EMS Other 11-Extinguishment by fire service personnel ID:PRV20 Type:00-Other apparatus/resource Dispatch:08/28/2025 07:10 Arrival: Clear:08/28/2025 10:46 Sent 1 Suppression EMS Other 80-Information, investigation & enforcement, other ID:PRV21 Type:00-Other apparatus/resource Dispatch:08/28/2025 07:32 Arrival:08/28/2025 07:41 Clear:08/28/2025 10:46 Sent 1 Suppression EMS Other 48-Remove hazardous materials ID:T1 Type:12-Truck or aerial Dispatch:08/28/2025 07:04 Arrival:08/28/2025 07:09 Clear: Sent 4 Suppression EMS Other 51-Ventilate A Page 8 of 16 NFIRS -10 Personnel 40060 CA 08 28 2025 Fire Station 1 (FS1) 25-05059 0 FDID State Month Day Year Station Number Exposure A Page 9 of 16 B Apparatus/Resource Dates/Times Sent Number of People Apparatus Use Actions Taken ID:BC2 Type:92-Chief officer car Dispatch:08/28/2025 07:04 Arrival:08/28/2025 07:09 Clear:08/28/2025 10:46 Sent 1 Suppression EMS Other 81-Incident command Personnel ID Name Rank Role Attend Actions Taken 62800 MacDonald, John Battalion Chief ID:CHIEF2 Type:92-Chief officer car Dispatch: Arrival:08/28/2025 07:15 Clear: Sent 1 Suppression EMS Other 55-Establish safe area Personnel ID Name Rank Role Attend Actions Taken 35110 Fox II, Samuel Battalion Chief 5588009-Chief Officer ID:E2 Type:11-Engine Dispatch:08/28/2025 07:04 Arrival:08/28/2025 07:21 Clear:08/28/2025 07:47 Sent 3 Suppression EMS Other 12-Salvage & overhaul Personnel ID Name Rank Role Attend Actions Taken 92710 Witt, James Captain 109137 Saunders, Cole Firefighter 74579 Robertson, Travis Engineer ID:E3 Type:11-Engine Dispatch:08/28/2025 07:04 Arrival:08/28/2025 07:10 Clear: Sent 3 Suppression EMS Other 10-Fire control or extinguishment, other Personnel ID Name Rank Role Attend Actions Taken 14845 Barrett, Richard Captain 99161 Hutslar, Dane Engineer 46543 Hicks, Judson Firefighter ID:E4 Type:11-Engine Dispatch:08/28/2025 07:04 Arrival:08/28/2025 07:09 Clear:08/28/2025 09:13 Sent 3 Suppression EMS Other 11-Extinguishment by fire service personnel Personnel ID Name Rank Role Attend Actions Taken 99187 Sensenbach, Mickey Engineer 66265 Nason, William Captain 100077 Greenelsh, Nathaniel Firefighter ID:PRV20 Type:00-Other apparatus/resource Dispatch:08/28/2025 07:10 Arrival: Clear:08/28/2025 10:46 Sent 1 Suppression EMS Other 80-Information, investigation & enforcement, other Personnel ID Name Rank Role Attend Actions Taken 109053 Daniel, Josh 5588016-Investigator Page 10 of 16 ID:PRV21 Type:00-Other apparatus/resource Dispatch:08/28/2025 07:32 Arrival:08/28/2025 07:41 Clear:08/28/2025 10:46 Sent 1 Suppression EMS Other 48-Remove hazardous materials Personnel ID Name Rank Role Attend Actions Taken 98956 Bliss, Matheson 5588015-Inspector ID:T1 Type:12-Truck or aerial Dispatch:08/28/2025 07:04 Arrival:08/28/2025 07:09 Clear: Sent 4 Suppression EMS Other 51-Ventilate Personnel ID Name Rank Role Attend Actions Taken 90841 Weis, Trevor Engineer 70100 Polkow, Matthew Captain 100069 DeLeuw, Casey Firefighter 50826 Johnston, Kenneth Engineer Page 11 of 16 NFIRS-1S Supplemental 40060 CA 08 28 2025 Fire Station 1 (FS1) 25-05059 0 FDID State Month Day Year Station Number Exposure Primary Narrative: BC 2 dispatched to the above location for a report of a structure fire with smoke and a fire reported by RP. BC 2 arrived on the scene and took over IC from T1. RP reported that everyone was out of the structure. Units at the scene were given assignments and conducted a fire attack and primary search. E3 found a lithium-ion battery in the area of origin. The FM arrived at the scene and was assigned safety. Once the fire was extinguished, the FM requested that we make contact with the Co. Haz Mat team. Prevention officer 22 arrived at the scene and worked with the two on-duty Haz Mat personnel to make contact with HM 1. Due to the smoke produced by the battery, HM 1 was asked to respond. HM1 and Prev. 22, along with the other HM personnel, worked to monitor and provide gas monitoring of the structure. Once the battery was properly secured and the home was found to be clear of hazardous conditions, all crews did a grouse decon at the scene, and the incident was then TOT BC 1 and BC 2 cleared. Please see additional narratives for further details. Additional Narrative (#1 of 5): E3 arrived at scene, assigned to assist E4 with fire attack. E3 operator/FF to interior back up/assist E4. E3 was also given utilities. E3 confirmed assignment and shut both electrical and gas off at structure side alpha entry way. E3 was asked to perform an ALL CLEAR secondary search of division 2. Origin of fire appeared to be a large battery located in the living room area, Operator 3 Haz Mat Hutslar removed/isolated battery to safe exterior location in street area. E3 back in service Additional Narrative (#2 of 5): Truck 1 was first on scene of a condominium complex fire with smoke and fire showing from the first floor. Truck 1 gave a size up and named incident "Exposition IC". Battalion 2 arrived and took over Exposition IC. Truck 1 established a water supply and 2 fire attack lines to the front door. Truck 1 split crew with captain and firefighter 1 on fire attack at front door and engineer 2 on ground ladders. Truck 1 was reassigned to ventilation just before entering the front door to attack the fire. Engine 4 took over fire attack and Truck 1 went to the roof for ventilation. Truck 1 went to the roof for a size up and was called off the roof by IC to horizontal ventilate the structure. Truck 1 was never inside structure and used positive pressure fans from outside the unit. Truck 1 was then in a support role for the remaining time on the incident. Additional Narrative (#3 of 5): Arrived on scene to find B2 in command of a structure fire. I was assigned Div Alpha, with E3, E4 working for me as interior fire attack crews. Crews relayed that fire was contained to the first floor with no extension. E-21 was assigned as 2 out and E-2 was assigned to assist with salvage and overhaul after fire knockdown was complete. Primary and secondary searches were completed on the first and second floor of the residence. Horizontal ventilation was performed by T1 crew. It was determined that the likely cause of the fire was a lithium ion battery pack, which was removed from the structure. E-3 was reassigned as Haz Mat Group to handle removing the battery and placing in an open area and performing gross decon of crew turnouts and equipment on site. A Page 12 of 16 Additional Narrative (#4 of 5): Engine 4 arrived on scene and was assigned Fire Attack by IC. Engine 4 acquired handline from Truck 1 FF, and made interior fire attack with Greenelsh and Nason. Fire was located in family room on first floor. Thermal camera showed active flame and heavy amounts of white smoke. Fire was extinguished with handline and continued to produce heavy white smoke. Engine 4 conducted mechanical ventilation with handline to remove smoke from division 1 of the structure. Engine 4 crew proceeded to search for extension on fire on Division 2, and confirmed no fire extension into wall space or Division 2. Engine 4 finished a primary search on division 1 and was all clear. Division Alpha was notified of the, "all clear on primary search." Engine 4 noted the source of the smoke was a lithium battery back producing chemical vapors. Engine 4 assisted with Hazmat Assessment, and gross decontamination of personnel. Engine 4 was released by IC to return to quarters for full decontamination of crew and equipment due to hazardous materials. Engine 4 crew remained asymptomatic, no medical, and successfully decontaminated crew and equipment. Page 13 of 16 Additional Narrative (#5 of 5): SLO FD FIRE ORIGIN & CAUSE INVESTIGATION REPORT DATE: 08/28/2025, 0703 HOURS LOCATION: 2220 EXPOSITION DRIVE, SUITE SAN LUIS OBISPO, CA 93401 PROPERTY TYPE: RESIDENTIAL CLASSIFICATION: ACCIDENTAL INCIDENT #: SLO-FD 25-037662 REPORTING OFFICER: DANIEL, JOSH; FIRE INVESTIGATOR (PREV 20); BLISS, MATTIE; FIRE INVESTIGATOR (PREV 21) REPORT #: SYNOPSIS This report documents the investigation into the origin and cause of a structure fire. ADDITIONAL RESOURCES 1. SLO COUNTY/ CAL FIRE Engine 21 2. SLO COUNTY Hazardous Incident Response Team (HM-1) SOURCE OF ACTIVITY On 08/28/2025, at approximately 0700, San Luis Obispo City Dispatch received a 911 emergency call reporting smoke and flames inside Suite 100 at 2220 Exposition Drive, San Luis Obispo, CA. Truck 1 was first on scene and established Exposition IC. Battalion Chief John MACDONALD arrived on scene took over IC. Truck 1 established a water supply. Engine 4 arrived and took over fire attack. Engine 4 crews stated the thermal imaging camera showed active flame and heavy amounts of white smoke. The fire was extinguished with a handline but continued to produce heavy white smoke. Engine 4 conducted mechanical ventilation with the handline to remove smoke from the first floor. It was reported that the fire was contained to the first floor with no extension. Primary and secondary searches were completed on the first and second floors of the residence. Engine 4 reported the source of the smoke was a lithium battery pack and assisted with a hazardous materials assessment and gross decontamination of personnel. INVESTIGATION My actions and findings result from the application of the scientific method, the recommended systematic approach to fire investigations, as outlined in NFPA 921, Guide for Fire and Explosion Investigations 2024 ed (NFPA 921). Methodology The methodology I utilized during this investigation consisted of identifying all available data for origin determination, including witness accounts, an initial scene assessment, development of a preliminary fire spread hypothesis, an in-depth examination of the fire scene, development of a final fire spread hypothesis, and identification of the fire’s origin. I identified all potential ignition sources, fuel packages, oxidizers, and circumstances. This information was utilized to develop fire-cause hypotheses and determine which hypothesis best fit the credible data available to identify the cause of this fire. Summary of Statements Address: 2220 Exposition Dr. Unit San Luis Obispo, CA. 93401 DOB: Phone: is the sole occupant of the residence and was interviewed by Fire Marshal DANIEL at the scene. He reported he was upstairs and had just unplugged the battery from the wall and removed his phone, TV, and DVD from being plugged into it. He began to hear a popping and banging noise. He also noticed a small amount of smoke. He walked downstairs to find the entire downstairs filled with smoke. He did notice a glow in the area of the battery. He left his apartment and called 911. had no medical needs during the interview. He reported the battery is over 5 years old but there had been no issues before the fire—no signs of heat, damage, smell, smoke, etc. The unit is a battery power source that is rated for 1800 watts. During a follow-up phone conversation on 9/4/25, stated that the power station cord had been unplugged from the device after it was fully charged. He stated he normally leaves the cord plugged into the [relocatable power tap] and the [relocatable power tap] plugged into the permanent wall outlet. Additionally, he mentioned that when he unplugged the cord from the device, the device was warm but not unusually hot after having been charging. END OF STATEMENT Scene Examination This fire scene consists of a multi-story residential condominium of wood frame, Type V construction located in an apartment complex. The home has at least one smoke detector and is sprinklered. Systematic Approach I began my investigation by walking through the fire scene, identifying all available data to determine where and how the fire had started noting the following: EXTERIOR Prior to investigating the residence, I observed a device cordoned off with traffic cones the middle of Exposition Drive outside of the entrance to the apartment complex. The device, roughly 14 cubic inches, was placed on the cover of a Styrofoam container and was stated to be a RV camper battery power source. Mass loss of material was apparent. The exterior materials of the unit had been consumed leaving the metal frame and exposed packs of cylindrical battery cells consistent with lithium-ion battery technology (IMG_3310-3311). The manufacturer make and model of the unit was not determined due to extent of damage to the device. “A” Side The “A” side faces south and includes the front door, garage door, and several second story windows. Smoke patterns nor soot deposition were observed on any openings (IMG_3309, IMG_3313-3319). “B”/ “D” Sides There are neighboring units on both sides of the residence. These units were not inspected. “C” Side The “C” side faces north. An enclosed patio is attached to the unit. A sliding glass door opens into the living area of the residence. An upper floor window can be observed from this side. No significant smoke patterns were observed on the exterior of this side (IMG_3323-3325). Page 14 of 16 INTERIOR Hall I entered the structure through the side A entrance door. I observed a short hallway that leads into the living room with a stairwell for the upper floors to the left (Side B), sliding glass door at the back wall (Side C), and the kitchen entrance to the right (Side A), adjacent to the living space. Minimal soot deposition was observed on the walls of the hallway leading to the living room (IMG_3328-IMG_3330). Living Room The living room appeared to have an average fuel load of common combustible materials for an inhabited structure. Furniture included a small couch and coffee table at the B/C corner, a TV and TV stand at the C/D corner, a reclining leather or vinyl covered chair and hutch/China cabinet on side D, and a glass dining room table with several chairs adjacent to the kitchen on side A. Several styrofoam containers were observed along the D side wall, in front of the TV stand, and near the reclining chair. Miscellaneous materials were observed in the styrofoam containers including a 1 lb. camping propane cylinder and one gallon of 4-cycle small engine fuel. The styrofoam containers showed minor blistering on the exterior, however, the contents of the containers were intact and appeared undamaged by smoke or heat (IMG_3344, IMG_3377). I observed a relatively even gradient of soot deposition—greatest at the ceiling and upper walls and lessening towards the floor with no clear line of demarcation. Soot deposition was most intense at the C/D corner (IMG_3342) and along Side D. A protected area on side D wall was observed from where a circular clock had been in place at the time of the fire (IMG_3345). In between the reclining chair and tv stand was a roughly 3ft diameter area of the carpet that was deformed, melted and had soot deposition on the outer perimeter. Additionally, items that had been in the area showed major mass loss and deformation, and melting into the carpet in areas. Some partially intact items were observed in the area including a pair of black shoes, various electronic components, a piece of clothing, and wetted cardboard (IMG_3340, IMG_3353). Additional cylindrical cells from a lithium-ion battery pack were observed in the area. Discoloration was observed on the footrest portion of the reclining chair greater towards the side D wall than interior of the living room (IMG_3358). A black cord was observed melted into a mass of deformed material and carpet and extending towards a relocatable power tap (RPT) at the side D wall (IMG_3370, IMG_3372, IMG_3396, IMG_3399, IMG_3400, IMG_3402). The cord was plugged into the RPT and the RPT was observed partially plugged into the permanent wall outlet at the time of the investigation (IMG_3382). Upon further investigation in the area, the plug came apart from the permanent outlet completely (IMG_3403-3405). The RPT switch appeared to be in the “on” position (IMG_3384, IMG_3404). The RPT was UL listed and rated for 15A (IMG_3407). No significant soot deposition, discoloration, or deformation of the RPT or adjacent cords was observed. Remaining exploded lithium-ion battery cells and other lithium-ion batteries believed to be damaged by water during fire suppression activities were removed from the area. An approximate 6” diameter area of the carpet had peeled away from the floor in the middle of the charred area during this overhaul activity (IMG_3422). Alarm/Smoke Detector/Protection/Security I observed one smoke detector in the living room located on the wall of the living room adjacent to the stairs. The detector was intact and reported to be working during the initial response. Area of Origin (AOO) After careful consideration that all credible data has been accounted for and all credible alternate origin hypotheses have been considered and eliminated, it is my opinion that the area of origin was a lithium-ion based portable power device located on the carpet in front of the reclining chair in the living room. AOO Competent Ignition Sources Competent ignition sources within the area of origin include the significantly damaged lithium-ion battery powered device and the 120v electrical outlet and connected RPT. Per witness statements, the device had been unplugged from the RPT prior to the fire; however, the RPT is normally left plugged into the permanent receptacle. Upon investigation, it appeared the RPT was partially unplugged from the permanent receptacle and may have been unplugged during overhaul activities. The RPT and several cords plugged into it and appeared to be in good condition with no major mass loss, deformation or discoloration. Per NFPA 921, for ignition to be from an electrical source, the following must occur: 1. The electrical wiring, equipment or component must have been energized from a buildings wiring, an emergency system, a battery, or some other source; 2. Sufficient heat and temperature to ignite a close combustible material must have been produced by electrical energy at the point of origin by the electrical source (NFPA 921). FIRE CAUSE 1. IGNITION SOURCE: lithium-ion battery thermal runaway 2. MATERIAL FIRST IGNITED: lithium-ion cylindrical cell 3. OXIDANT: Oxygen from surrounding air, oxygen bound in battery chemistry 4. EVENT WHICH BROUGHT IGNITION SOURCE AND MATERIAL FIRST IGNITED TOGETHER: There are many reasons why a lithium- ion battery may fail and proceed into thermal runaway. Environmental or mechanical damage, electrical overcharge/over dis-charge, external short circuit, design and manufacturing flaws, and aging are forms of abuse that can destabilize the battery chemistry (Barowy, A. (2023). The science of fire and explosion hazards from lithium-ion batteries. Fire Safety Research Institute. Retrieved from https://d1gi3fvbl0xj2a.cloudfront.net/2023-01/The%20Science%20of%20Lithium- Ion%20Batteries%20Guide%20by%20FSRI_1.pdf) SKETCH See attachment. PHOTOS 114 DIGITAL PHOTOGRAPHS WERE TAKEN AND UPLOADED TO THE ELECTRONIC CASE FOLDER EXPOSURES 1. ACTUAL EXPOSURES: Interior of residence. The interior of the garage was not observed during the investigation. 2. POTENTIAL EXPOSURES: Neighboring residences. NUMBER OF FATALITIES AND/OR INJURIES No fatalities or injuries were a result of this fire. CONCLUSION Based on witness statements and the physical evidence found in the AOO, no other competent ignition source outside of the lithium-ion battery powered device could have started the fire. The observed fire effects on the carpet and surrounding furniture and walls demonstrate spread of fire from the device to the to the surrounding area. CLASSIFICATION OF THE CAUSE ACCIDENTAL: The proven cause does not involve an intentional human act (2017 NFPA 921 20.1.1) Page 15 of 16 My opinion of the origin and cause of this fire is based on the following: 1. My more than (2) years of professional fire investigations 2. I have personally conducted and/or assisted in over (20) fire events 3. I have over (230) hours of fire investigation and related law enforcement training END OF INCIDENT REPORT Apparatus Narrative for BC2: Apparatus Narrative for E2: Unknown Apparatus Narrative for E3: PPE Apparatus Narrative for E4: PPE Apparatus Narrative for T1: MDC down and turn out time for first in unit on confirmed fire. Page 16 of 16