MADRID, Feb. 6 (Xinhua) -- Two people were killed and another seriously injured in an explosion in a biodiesel plant in the town of Algemesi in east Spain on Saturday.

The explosion happened around 11:00 a.m. local time in an industrial estate on the outskirts of Algemesi, 33 km south of Spanish port city Valencia.

The two victims were workers who were reportedly to be in their 40s, while the injured person had burns on 80 percent of his body, according to Marta Trenzano, the mayor of Algemesi.

The cause of the explosion has not yet been found. Some believe the accident could be caused by people soldering a storage silo, which contained residual flammable gas.

Local authority has declared Monday as a day of mourning for the victims.