On February 26, 2018, explosive materials of an unknown age and unknown stability were identified at associated outbuildings located in close-proximity to a residential structure located at the incident Property. The Shasta County Explosive Ordinance Disposal (EOD) team evaluated the discovery and determined that stockpiles of highly explosive materials and associated materials which included blasting caps, detonation cord, smokeless powder, etc., (collectively the “Materials”) were stored on the Property.
Further evaluation by the EOD team on February 27, 2018 resulted in the decision to order mandatory evacuations within a ½ mile radius of the Property as remediation and disposal of the Materials were undertaken by the EOD team. Approximately 150 pounds of explosives were safely destroyed by the EOD team, however there remained approximately 150 to 200 pounds of Materials at the Property. These remaining Materials were in an extremely cramped and cluttered environment which made for investigation, remediation, safe removal, and other safety problems that required the continuing application of multiple local and state resources.
A determination was made to secure the Property and lift the mandatory evacuations as the EOD team, in conjunction with our local and state partners, evaluated and developed a remediation plan to render the Property safe.
On February, 28, 2018, a meeting was conducted with the Emergency Management Council. Upon the conclusion of the meeting it was determined, with the remaining explosives on scene, the least dangerous method to render the Property safe was to destroy the two story outbuilding through a controlled burn. The Sheriff’s Office remained in unified command with the Happy Valley Fire Department for this event.
A detailed plan was developed by staff for evacuation, sheltering needs, incineration, re-population and determining how the property and area would be deemed safe. Multiple variables (weather and location) were taken into consideration in the planning. The EOD Team worked diligently, in harm’s way, to remove as much explosive items as possible from the two story outbuilding working a majority of the time in cramped and unsanitary conditions while also dealing with extreme weather conditions which increased the danger of handling the explosive items. The team was even forced to postpone one of the planned detonations of some of the explosives due to the weather.
It was determined the best day to conduct this controlled burn would be Monday, March 5, 2018. The evacuation radius for the burn was one-half mile, which directly impacted about 100 homes in the area and forced the closure of the Happy Valley Union Elementary School District. Even with detailed planning and removal of as much explosive items as possible, there still remained the possibility of detonation of the remaining explosives; as such evacuations that were ordered again on March 5th remained in place until the conclusion of the controlled burn. Air quality monitoring was set in place to record air samples before, during and after the burn.
On Monday, March 5, 2018, at about 1042 hours, The EOD Team initiated the controlled burn. A water curtain was turned onto the main house in effort to protect it from damage. At about 1046, it was reported there was positive ignition from the remote ignitors. As a result, the two story outbuilding was successfully destroyed. Additionally, a conex box and an uninhabitable trailer were also destroyed due to the fire.
Air quality samples taken of the area during the burn operation revealed no negative impact to air quality. At 1500 hours, the evacuation order was lifted and all residents were allowed to return home. Upon inspection of the main residence there was no significant damage noted from the fire. A small road closure remained in effect until the EOD Team could return to the scene the following day and safely check the area.
On Tuesday, March 6, 2018, the EOD Team returned to the scene and conducted a meticulous search of the area. While searching the remains of where the two story outbuilding once stood, the EOD Team located a partially damaged, unexploded, hand grenade. The EOD Team was able safely destroy the hand grenade on scene. At about 1400 hours, the scene was declared safe and the remaining road closure was lifted.
Shasta County Environmental Health will be working with the property owner to ensure the site is cleaned up in a timely manner.
At this time it is recommended that the Board of Supervisor’s adopt a resolution declaring the local emergency no longer exists.