South Metro Fire Rescue and Arapahoe County Sheriff's deputies raced to a burning electric vehicle on eastbound Arapahoe Road, just east of South Waco Street, just after 7 a.m. Tuesday. The driver got out safely and no one was hurt, but what followed was hours of road closures, a half-mile shelter-in-place order and a hazmat cleanup involving thousands of scattered lithium-ion battery cells.
Crews with Engine 42 determined the vehicle's lithium-ion battery had entered thermal runaway, a process in which damaged battery cells rapidly overheat and can cause neighboring cells to ignite, according to the seed facts from South Metro Fire Rescue. As reported by CBS News Colorado, crews rushed to the burning electric vehicle near Arapahoe Road and Waco Street Tuesday morning, and Arapahoe Road was closed in both directions while fire crews worked the scene.
Firefighters established a safety zone of more than 300 feet around the vehicle and made the call to let the battery fire burn itself out while crews monitored conditions, per the seed facts. South Metro's hazmat team also responded to the scene to track air quality and chemical exposure risks as the fire continued to smolder.
Half-Mile Shelter-in-Place Ordered Within Minutes
The Arapahoe County Sheriff's Office issued an ArapAlert citizen notification at 7:36 a.m., advising anyone within a half-mile of the fire to shelter in place. Residents were asked to remain indoors, close their windows and doors, and turn off HVAC systems that draw in outside air, a precaution CBS News Colorado also noted citing toxic smoke risk. South Metro Fire Rescue's hazmat team used air monitoring equipment at Our Lady of Loretto Catholic School to confirm conditions were safe, the station notes, quoting the fire crew saying, “We sent in our hazmat team with air monitoring into the school to make sure it was safe, which it was,” according to KDVR. The shelter-in-place order was lifted at 8:23 a.m. Tuesday, though the seed facts put the time at 8:25 a.m.
The roadway reopening took longer to resolve. One lane of Arapahoe Road reopened at 10:31 a.m. once crews had cleared the scene and extinguished the fire, the station's report states. South Metro Fire Rescue also warned that water used to fight the blaze was contaminated and should not be allowed into a storm drain or waterway, per the same account.
Conflicting Accounts of What Sparked the Fire
Exactly what set the vehicle ablaze remains disputed. CBS News Colorado reported that investigators said the fire was caused by an abandoned tow hitch left in the road, with at least four vehicles striking the hitch before the fire broke out. KDVR, however, reported that the Arapahoe County Sheriff's Office said a skid steer fell off a commercial towing vehicle and stripped the bottoms of cars behind it before striking the lithium battery under a Tesla.
The Arapahoe County Sheriff's Office is investigating the cause of the fire, according to the seed facts and confirmed separately by KDVR's reporting. The crash and fire left thousands of lithium-ion battery cells and other debris scattered at the scene, and an independent hazardous materials mitigation company was brought in to collect, overpack and properly dispose of the damaged battery material.
Why Firefighters Treat EV Battery Fires Differently
South Metro Fire Rescue's response strategy for the incident prioritized isolating the vehicle, protecting the public, monitoring conditions, and limiting exposure to smoke and gases rather than attempting to douse the battery fire outright. That approach reflects a broader shift in how fire agencies handle electric vehicle fires as the technology becomes more common on the road.
Damaged electric vehicle batteries can produce extreme heat, prolonged burning, hazardous gases and the risk of re-ignition, and hazardous gases released from lithium-ion battery fires can include hydrogen fluoride, per the seed facts. Research from the Fire Safety Research Institute notes that thermal runaway and fire incidents involving these vehicles can be expected to occur with greater frequency as EVs become more prevalent. A separate FSRI research update found that EV battery fires can produce elevated levels of metals, particulate fluoride, PAHs and VOCs, though the same research found each tested vehicle typically burned out within approximately 90 minutes once ignited.
The Los Angeles Times reported that excessive heat inside a battery creates a self-sustaining chemical reaction called thermal runaway that can easily spread to adjacent batteries, and that large, multiple-battery fires can burn for days while releasing toxic gases including hydrogen fluoride, hydrogen chloride, carbon monoxide and carbon dioxide. That dynamic played out in La Verne last month, where roughly 200 homes remained under evacuation orders for a second day while crews worked to stabilize lithium-ion batteries burning inside a water district facility, with one civilian injured at the outset of that incident.
Crews Took Precautions Against Battery Re-Ignition
Once the Arapahoe County fire was out, firefighters placed an electric vehicle fire blanket over the vehicle, a tool that may help contain potential re-ignition during transportation or storage, according to the seed facts. The vehicle was then removed from the scene by a tow truck accompanied by South Metro Fire Rescue apparatus and ultimately transported to a tow yard, CBS News Colorado reported.
That caution is grounded in documented risk: damaged batteries can reignite hours or days after they are initially extinguished, including while an EV is in transport or storage, according to a study from the Washington State Patrol. Locally, KDVR has also reported that lithium-ion battery fires are becoming more common, with Adams County Deputy Fire Chief James Wood saying, “We're seeing more and more of these lithium-ion-based battery fires,” in a separate incident where a north Denver home caught fire after an EV battery reportedly sparked in a garage and the flames spread into the attic and along the length of the house.
What South Metro Fire Rescue Wants the Public to Know
Lithium-ion batteries are used not just in cars but in commercial vehicles, buses, e-bikes, power tools, phones and laptops, and damaged, improperly charged or improperly stored batteries can overheat, catch fire or enter thermal runaway, per the seed facts. South Metro Fire Rescue is urging anyone who sees a lithium-ion battery fire to stay away and call 911, and not to attempt to extinguish a burning electric vehicle or large lithium-ion battery themselves.
The department also encourages residents to follow a buy, charge and recycle safely approach when it comes to battery-powered devices, and is urging residents to sign up for their county's emergency notification system following Tuesday's scare.
