TEMPE, AZ (AZFamily) — A bus exploded in flames on a Tempe off-ramp on Monday night.
It happened on the Priest Drive off-ramp from the Loop 202 Red Mountain Freeway just before 9:30 p.m.
A bus exploded in flames on a Tempe freeway off-ramp.(ADOT)
Video from an Arizona Department of Transportation camera showed the bus right at the intersection catching fire. The flames were shooting out both sides of the bus.
When Tempe Fire crews arrived, the bus was already engulfed in flames. Firefighters worked quickly to begin putting out the fire.
“The bus’s compressed natural gas (CNG) tanks began venting during the incident, prompting a cautious and coordinated response to ensure the safety of everyone on scene. Crews worked methodically to control the fire and verify that the CNG tanks remained intact and no longer posed a hazard,” said Tempe Fire Medical Rescue Department Assistant Chief Anthony Butch.
CNG tanks performed as designed
Compressed natural gas is made up mostly of methane and weighs less than air. David Clement with CNG Services of Arizona says the sight of flames shooting into the air is actually a sign that the CNG tanks were properly venting.
“The tanks did what they were supposed to do. The relief valves vented. It got the gas out and away, so you don’t have an explosive event,” Clement explained. “On CNG tanks, they’re all built inherently with relief systems that are triggered by pressure or temperature.”
Firefighters with the Phoenix Fire Department also responded to the scene. Captain Mike Johnson says that in recent years, fires like these have been becoming more common and the department has trained more on how to handle them because they can be unpredictable.
“We have taken extra steps in doing some more training with these CNG vehicles, how to recognize the threats with the placards and just kind of the initial plan of the first new engine that’s going to be on scene of that,” said Johnson.
Valley Metro said the bus had no passengers and was returning to its East Valley maintenance facility before the driver noticed fire in the rear of the bus.
Smoke could be seen for miles but didn’t affect planes going to and from Phoenix Sky Harbor Airport.
No one was hurt in this response, but the cause of the fire is still under investigation.
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