(RIVERSIDE, Calif.) -- On Friday evening, the Riverside County Fire Department reported that 35 employees at a transportation company fell ill after exposure to an unknown substance.
Fire and rescue crews were sent to the scene at 7:47 p.m. local time on Friday. The RCFD says that the employees at Swift Transportation were "overcome by an odor of an unknown substance in a trailer."
The first 19 employees were taken to a nearby hospital by ambulance. Sixteen more were taken to the hospital on a pair of buses operated by the Riverside Transit Authority.
After further investigation, the RCFD said that the substance was sodium benzoate, a food preservative which, when combined with moisture, turns into an irritant. The 35 employees were treated at area hospitals.
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