HIGHLANDS RANCH — Authorities have charged a Highlands Ranch charter school student with one felony count of possession of an explosive or incendiary device and five misdemeanor assault counts.

The charges stem from a chemical blast last month at the SkyView Academy that sent five students and a teacher to the hospital.

KMGH-TV reports (http://bit.ly/1dRf5an ) that authorities cannot release the male student's name because he is a juvenile.

Douglas County investigators initially detained two juvenile males in the Jan. 14 incident, which involved a chemical reaction causing a container to rupture.

But a spokeswoman for the District Attorney's office says the investigation found only one juvenile culpable.

There was no damage to the classroom and those taken to the hospital were treated and released.