A vac truck explosion Tuesday morning in Southern California has hospitalized more than 15 people after a hazardous chemical waste spewed from the truck. The vac truck explosion resulted in the spill of about 1,000 gallons of unknown liquid, later causing a huge blaze that prompted around 55 firefighters to put out, according to Tom Kruschke of the Ventura County Fire Department.

The vac truck explosion occurred around 6:30 a.m. at the Santa Clara Waste Water Company in Santa Paula, a city east of Ventura, KNBC-TV reported.

When the vac truck explosion around 3:30 a.m., two drivers were inside the truck. It caused major spillage of a white liquid which at first was thought to be sewage. The white liquid later turned out to be combustible after it crystallized. The rig was used to suction up industrial waste.

Kruschke told KPCC that the fire department received the call for the vac truck explosion around 4 a.m. At first it was an injury at Mission Rock Road, west of Santa Paula and south of Highway 126. The vacuum truck had been removing chemical contents from a storage container when the vac truck explosion occurred.

Eventually, the white liquid from the truck spread through the industrial yard. Several small explosions thus followed and soon a fire extended throughout the industrial yard. The vac truck explosion prompted shelter-in-place warnings and road closures since nobody had an idea what chemical they are being exposed to.

Billowing black smoke soon appeared overhead and into the sky, thus forcing the California Highway Patrol to shut down Highway 126 between Peck Road and Wells Road.

Firefighters fought the blaze caused by the vac truck explosion for several hours. According to NBC Los Angeles, over 50 firefighters from Ventura, Oxnard and Ventura County fire departments responded to the scene.

Fire officials said the white liquid released from the vac truck explosion is organic peroxide.

"We have since determined that the contents were an organic peroxide," said Kruschke. "The problem we're having is that as it [the chemical content] is exposed to the wind and weather, it dries out, crystallizes and can spontaneously combust."

Kruschke added that some of the workers at the scene of the vac truck explosion, including firefighters and ambulance personnel, were exposed to the chemical and had been contaminated.

"It took us a while to determine that there was this problem and what was happening with this chemical," he said. "So we ended up with two incidents going on at the same time."

KNBC reported that around a dozen hospital workers were treated for respiratory distress at Ventura County Medical Center. Three firefighters and two of the waste water company's employees were also hospitalized due to contamination to the chemical substance. Some of those contaminated complained of respiratory problems or skin irritation.

More firefighters as well as an inmate from the Todd Road Jail were also taken to the hospital as a precaution, reports KPCC.

Kruschke said 55 firefighters in total and 100 plus people from other agencies are now working together to handle the incident. The Los Angeles County Fire Department also sent in hazmat teams to assist with the vac truck explosion incident, they said via Twitter. 

According to police, mandatory evacuations were held amongst residents within one mile of 815 Mission Rock Road. Those living within three miles of the site were meanwhile ordered to shelter in place.

"(Our) primary focus and concern is for the safety of our employees and community," Doug Edwards, chairman of the board for the Santa Clara Waste Water Company, told an NBC affiliate.

As of the current moment, extent of the injuries from the vac truck explosion remains unclear, reports the New York Daily News.

As for environmental worries, an environmental official said that despite precautions, there is no need for much worry from the vac truck explosion. Since the facility treats waste water and has a catch-basin mechanism underneath the plant, the ground will reportedly be protected.

According to Rick Bandelin from Ventura County Environmental Health Division, those living nearby should in the meantime just avoid the smoke, as they would with any situation involving fire.

Cause of the vac truck explosion is still unknown by company officials. "Obviously we've had a terrible accident and I don't know the reason for it yet but I do know we will respond to it appropriately," said Doug Edwards, chairman of the board for the Santa Clara Waste Water Company.