An explosion in a junior high school chemistry laboratory left a teacher and three students injured Monday, according to media reports.

The incident was first reported to the police at 2 p.m. at Junior High School 4 in the Pueblo Nuevo area.

Police agents and firefighters were deployed to the scene right after the explosion of an unknown chemical was reported.

The teacher, who was only identified as Juana, told the authorities she was cleaning the laboratory when the explosion took place.

The teacher had injuries in a leg.

According to the teacher the explosion took place after opening a container with a greenish substance.

Two 14-year-old students and a 15-year-old one were affected after inhaling of smoke. The students also had irritated skin.

Hazardous chemical specialists decontaminated the laboratory.