A tanker truck filled with liquid hydrogen caught fire Wednesday in an El Cajon business park, Heartland Fire & Rescue officials confirmed.
Firefighters were called to Veridiam, a manufacturing plant located at 1717 Cuyamaca Street just after 8 a.m. for a report of an explosion.
They found a tanker truck known to be carrying between 1,500 to 2,000 gallons of liquid hydrogen on fire.
"It felt like a really small earthquake," Kyle Feliberty said. He works at a business near Veridiam. "The walls kind of shook a little bit, loud crash, but it didn't last long like a normal earthquake would."
Hazmat crew members were making entry into the area just before 10 a.m.
“The product is being burnt off as it’s venting so there is no hazmat issue that residents should be concerned about. If you’re sheltered in place, you should be OK at this time,” said acting Battalion Chief Chris Case.
The venting process was part of an automatic safety feature on the truck, Case said. It began while crews were offloading the truck's product.
The fire was contained to the truck and there did not appear to be evidence that the truck exploded, Case said.
Case said he was not told what started the fire.
"The product is flammable and when it's exhausted from a vent there are a number of things could spark a flame," Case said.
It was not clear what the liquid hydrogen was being used for at Veridian. The tanker was delivering it there.
Approximately 150 students from IDEA Center, Chaparral and Merit Academy were moved to Grossmont High School.
Busses pulled into one of the campuses to load the students for the drive to Grossmont HS located at 1100 Murray Drive. By 9:30 p.m., a district spokesperson said all students were removed from the area.
Fire officials warned nearby businesses and residents to avoid the area for four hours.
El Cajon police officers were also called to help handle traffic.
San Diego Metropolitan Systems said the Sycuan Green Line was rerouted at Arnele Station and the Orange Line was rerouted at El Cajon Transit Center. Commuters using these trolley lines should expect delays.
The business park is located south of Gillespie Field, east of Cuyamaca Street and north of Fletcher Parkway. It is situated directly across the street from Idea Center High School and a block from Chaparral High School.
Ed. Note: Heartland Fire-Rescue officials initially reported the explosion at a different address. The correct address is listed in this version of the article.