Police say three people were injured in an explosion caused by drug processing at a Mount Vernon apartment.

Police say three people were injured in an explosion caused by drug processing at a Mount Vernon apartment.

Lt. Chris Cammock told KIRO ( http://www.kirotv.com) firefighters put out flames ignited by the blast just before midnight Thursday and three were treated at a hospital for minor burns to the arms and faces.

Cammock says the residents were using butane to extract oil from marijuana when something ignited the fumes.

Information from: KIRO-TV, htthttp://www.kirotv.com/index.html