Caltrans says the crash happened on Highway 99, just south of the Highway 180 interchange, on Friday morning.
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CHP Officers say a Ford F-250 was driving northbound on Highway 99, when the driver was involved in some sort of incident that caused pipes in a flatbed trailer being towed by the pickup truck to spill into the opposite side of traffic.
Those pipes caused a Peterbilt tractor-trailer on southbound 99 to go up an embankment and a Freightliner truck to spill diesel fuel onto the highway after colliding with them.
Officers say four other vehicles struck the pipes as well.
No one was seriously injured.
Investigators say the fast actions of CHP officers contained the leaking diesel fuel before it went into a water drain.
The Fresno Fire Department HAZMAT team was called out to help clean up the diesel fuel off the freeway.
CHP Officer Herctor Carias says the westbound Highway 180 connector ramp to southbound Highway 99 has reopened. The eastbound connector ramp remains closed.
Drivers are advised to find alternative routes. It's unknown how long the closure will last.
Stay with ABC30 for the latest details on this developing story.