A propane tank behind the Target store at South Napa Marketplace near Imola Avenue caught fire yesterday, sending flames shooting from its relief valve and forcing an evacuation of the store. The blaze broke out around 3:30 PM and prompted firefighters to temporarily shut down Gasser Drive as they worked to contain the danger.
Firefighters arriving at the scene found a 200-gallon propane tank heated up and flaming at the relief valve, according to the Napa Valley Register. Crews hosed down a nearby gas main and the back of the store as a precaution while the tank burned. Napa Fire Captain Aaron Baracco told the paper that the tank ran out of propane and the fire went out on its own after about 25 minutes.
Valve Did Exactly What It Was Designed To Do
Baracco said the relief valve performed as intended, venting the excess pressure rather than allowing it to build toward a failure. Per Baracco, the same valve could have caused an explosion had it failed instead of venting properly. That distinction lines up with how the hardware is engineered to work: under NFPA 58 standards, propane tank pressure relief valves are built to open automatically when internal pressure spikes, releasing gas to prevent a catastrophic boiling liquid expanding vapor explosion, or BLEVE, according to guidance published by Industrial Monitor Direct.
The exact reason the tank overheated in the first place remained unknown yesterday, the fire captain said. Liquid propane expands quickly as it warms — roughly 0.2 percent per degree Fahrenheit, according to Industrial Monitor Direct, meaning a 50-degree temperature swing in trapped liquid lines can generate up to 165 psi of extra internal pressure. Federal rules add another layer of context: OSHA standard 1910.110 and NFPA 58 require commercial propane containers in the 125-to-500-gallon range, like the one behind the Napa Target, to sit at least 10 feet from nearby structures and property lines.
A Familiar Response for a Nearby Fire Crew
Firefighters were able to reach the scene quickly in part because of geography. Napa Fire Station 4 sits at 251 Gasser Drive, only about half a mile from South Napa Marketplace, giving crews a short trip to the Target loading area once the call came in. The shopping center itself dates back to land purchased in 1947 by the Gasser family foundation and today anchors a retail corridor that also includes Raley's and Home Depot.
Letting the tank vent and burn out under a steady stream of water is standard hazmat practice for this kind of incident. Fire crews elsewhere have used the same cool-and-contain approach, including during a large propane tank leak near Puyallup's South Hill that required continuous hose streams on the tank shell and nearby exposures. A similar dynamic played out in June when a commercial vehicle hauling propane tanks caught fire on Highway 162 in Northern California, rupturing a valve line and triggering a multi-agency road closure.
Growing Call Volume in a Fast-Changing Corridor
Thursday's fire adds to a steadily rising workload for Napa's fire department. The agency operates five stations with 77 total personnel and logged 11,448 calls in 2022, an 86 percent jump in call volume over two decades that city officials attribute largely to commercial and residential growth in areas like South Napa. The incident also comes just weeks after Napa adopted its first wildfire protection plan following years of wildfires that burned roughly 65 percent of the county's land.
No injuries were reported. Investigators have not said whether the tank's relief valve had recently been inspected; industry guidance under NFPA 58 and related compressed-gas codes recommends replacing or requalifying such valves every 10 to 12 years. What triggered the pressure spike behind the Napa Target remained an open question as of Thursday evening.
