An  18-year-old man and a juvenile were injured Monday night by an explosion that occurred while the pair were making model rockets at a Thousand Oaks school, fire officials said. The man suffered critical injuries and later died at a hospital, Ventura County sheriff’s Det. Tim Lohman said late Monday.

Shortly after 7:30 p.m., Ventura County fire officials were called to Madrona Elementary School in the 600 block of Camino Manzanas on the report that a rocket had exploded in a person’s hands, fire Capt. Mike Lindbery said.

Firefighters discovered that the two people were using a small propane cylinder to make a model rocket, and that the cylinder had apparently exploded, Lindbery said. The juvenile was also taken to the hospital with minor injuries. He remained hospitalized in stable condition, Lohman said. Investigators from the fire department and the county Sheriff’s Department were at the school, examining what led to the explosion.