Here's a press release from the Kennewick Police Department:

Summary of Incident: On December 13, 2018 at about 12:35 pm the Kennewick Police and Fire Departments responded to 2303 W 15th PL for a report of an explosion. When emergency services arrived they found fire inside a small room within the residence. They also found an adult female, later identified as Lenne Parson and four elementary aged children safely in the yard. Parson was transported to Trios Hospital with apparent injuries and one of her children was transported as a precaution.
Based on the initial investigation it appears that Parson was allegedly producing marijuana oil with the use of a flammable gas which ignited and caused the explosion and resulting fire. The investigation is on-going and any criminal charges will be determined at a later date in conjunction with the Benton County Prosecutor's Office.
We would like to remind people that the use of flammable gasses near an ignition source is extremely dangerous and can cause death or serious bodily injury. The use of them for the purpose of extracting marijuana resin by anyone other than a licensed professional is illegal.