ROSSVILLE, WALKER COUNTY (WRCB)-- Channel 3 is learning more about a home explosion that rocked a Rossville neighborhood Wednesday night. 

Officials with the State Fire Marshal's office continued their investigation on Mission Ridge Road Friday morning. Sniffer dogs walked the property, but nothing meth-related was detected.

While investigators haven't determined an official cause, they believe the explosion could stem from a 60-year-old septic tank.

A methane detector found levels of the chemical were three times higher than usual. Investigators believe a seal on an iron pipe came loose, triggering the explosion. 

Officials were able to rule out several causes, Thursday.

They say the electricity was turned on, and natural gas is not used in the neighborhood. 

Stay with WRCBtv.com for updates to this developing story.