The Marshalltown Fire Department has concluded their investigation into the fire that occurred on Saturday, January 21, 2017 at the JBS Processing Plant located at 402 N. 10th Avenue. Investigators believe that on the morning of the fire the following events occurred:
- JBS staff ignited a pressure relief torch in the methane retention system to burn off excess gas that had accumulated.
- Some debris had accumulated within the burner area of the torch and ignited. Aided by the wind, the embers dropped down and ignited methane gas that was venting around the manhole cover to the influent water system to the lagoon.
- The fire is believed to have burned along the border of the manhole cover, then igniting an overflow hose leading to the top membrane of the lagoon system. Once compromised, methane gas began leaking through the membrane covering causing ignition of the gas.
The fire has been classified as unintentional and the investigation completed.
