The substance inside the truck at the Santa Clara Waste Water Company was initially thought to be sewage, NBC Los Angeles reported. However, investigators determined the truck was spraying a white chemical that crystallized and became combustible shortly before 4 a.m. PT.
The chemical was an organic peroxide, according to KCAL, and the truck was carrying about 1,000 gallons of the substance.
There was a series of small explosions that set off a larger fire throughout the plant's yard. People within a mile radius of the facility were evacuated. Workers at the treatment plant as well as residents living between one to three miles away were told to shelter in place.
Both operators of the vacuum truck were inside the vehicle when the explosion occurred, and at least one of them was sent to the hospital. Three firefighters and and an ambulance worker were hospitalized after complaining of breathing trouble. A dozen hospital workers also were reportedly treated for respiratory issues.
A vacuum truck uses suction lines to collect solids liquids, sludge and other substances into a tank. These types of trucks are typically used for sewage or to empty septic tanks.
Copyright 2014 Raycom News Network. All rights reserved.