Investigators Say Robbins Lumber Silo Blast Was Accidental

Overview

• The silo at Robbins Lumber, which exploded May 15, was blown off its concrete base then toppled and spread fire to nearby mill buildings.
• Investigators concluded the blaze began in the unloader mechanism at the base of a sawdust silo when suspended particulate material rapidly ignited inside the vessel.
• The facility’s top‑mounted fire suppression system did not activate because temperatures at the sensor elevation never reached its activation threshold.
• The May 15 blast killed Morrill volunteer firefighter Andrew Cross and injured about a dozen other first responders and mill workers while causing extensive damage that has shuttered parts of the complex.
• State and federal teams completed the initial on‑scene examination and began demobilizing but say the probe remains active and that they will return for detailed testing with ATF, insurers and outside technical experts.