TIJUANA (Border Report) — The gas explosion that killed four and injured three others on April 12 at a Tijuana natural gas plant has been ruled accidental by the Tijuana Fire Department.

Rafael Carrillo Venegas, head of the fire department also ruled out sabotage.

“We’re still finishing up the investigation, but from what we’ve been able to find out we can be certain it was an accident,” he said. “This being intentional has been ruled out, nothing shows up in the videos and other factors.”

The owners of the plant say a valve malfunctioned.

Shrapnel and other debris blew into a nearby call center located within the premises, killing four female employees and injuring three others.

The storage tank, which held 3,000 liters of natural gas, or about 800 gallons, caught fire after it blew up.

The tank is normally used to refill smaller containers that are rented or sold to customers who don’t have gas delivered to their homes via gas lines.

The facility is located on the east side of Tijuana where residents are now calling for its relocation.

But management says it has no plans to move the plant since they were in the area first.

Tijuana’s director of civil protection, Bernardo Villegas, said the city has not made a decision on seeking a move for the plant.

“This company has been reached by urban development and maybe at some point they will have to move, but that’s not something the city is looking at now,” said Villegas.