TWIN FALLS, Idaho (AP) — The Idaho state fire marshal says investigators were unable to find exactly what caused an explosion at Rep. Fred Wood's southern Idaho home in September. Wood's wife Amy Wood received second-degree burns and was hospitalized for about three weeks when she was engulfed by flames from the explosion.

The Times-News reports that the state fire marshal's office released a report Wednesday concluding that oily rags may have self-ignited and caused the Sept. 29 explosion in the basement of the home, but investigators didn't find any concrete, single cause. According to the report, the cause will be officially listed as undetermined unless new evidence is found.