Thursday morning’s commute on the 91 Freeway in Riverside turned into an abrupt standstill after a truck fire set off a hazmat scare and shut down both eastbound and westbound lanes at Adams Street. The California Highway Patrol reported a strong propane odor in the area and warned of a “high explosion probability,” prompting crews to freeze traffic in both directions while hazardous materials teams moved in to secure the scene. Officials are still sorting out the details of the crash itself and whether anyone was hurt.
As reported by CBS Los Angeles, the CHP issued a SigAlert for a hazmat situation at SR-91 and Adams Street and said the closure was expected to last about two hours. The station noted that the agency first pushed the warning to drivers through a social media alert.
Traffic snarls and detours
It did not take long for traffic to back up across the Inland Empire as drivers were forced off the freeway and onto surface streets. Incident logs showed multiple hazards popping up on SR-91 during the morning rush, a familiar chain reaction for regulars on the corridor. CommuteDash’s real-time feed recorded the SigAlert and a string of incidents on SR-91 that morning, underscoring how one closure can ripple across the entire route. Authorities urged drivers to steer clear of the area while emergency crews secured the scene and worked to clear debris.
Why propane releases raise explosion concerns
Propane and other liquefied petroleum gases can pool into dense, low-lying vapor clouds that are notoriously easy to ignite if they encounter a spark. That can lead to flash fires or, in rarer cases, vapor-cloud explosions that extend the danger far beyond the vehicle involved. Federal safety guidance from the Pipeline and Hazardous Materials Safety Administration explains why LPG releases trigger broad exclusion zones, and specialized hazmat tactics, and researchers at the National Academies emphasize that vapor-cloud behavior is a key concern for first responders. That risk profile is what led crews on SR-91 to hold all lanes while specialists checked for leaks and any potential ignition sources.
What officials said and what’s next
The CHP told CBS Los Angeles that they expected the closure to last roughly two hours while hazmat teams evaluated the truck and the surrounding area. Once they deem the scene secure, investigators will turn to figuring out what sparked the blaze, and the involved agencies will coordinate to reopen lanes as soon as they decide it is safe to let traffic roll again…