Firefighters in Greeley, Colorado recently responded to a propane tank explosion at the Leprino Foods construction site, where they found a cargo container destroyed by the explosion. The Leprino Foods plant is currently under construction. The explosion happened in a steel cargo container used by the construction contractor for the temporary storage of epoxy floor coating in 5-gallon buckets.  The cargo container was located outside of the plant buildings in an area used by the contractor for storage of construction materials and supplies.

The epoxy coating could not be allowed to freeze, so the contractor installed a propane space heater inside the container, mounted to the wall.  This particular space heater was designed for home use with a source of natural gas or propane located outside of the space being heated.  The heater operates with a pilot flame to light the main burner.  The pilot flame is continuously lit.

It is apparent from photographs posted by CBS news in Denver and from the Greeley Fire Department’s incident report that the source of propane for the heater was a portable tank located inside the cargo container.  Fire department investigators believe that the propane line or regulator at the propane tank started to leak and filled the container with propane. The propane gas then ignited when it contacted the pilot flame inside the heater enclosure. The force of the explosion ripped open the cargo container and threw the propane tank more than 100 feet from the trailer, knocked down several portable toilets and damaged a car in the nearby parking lot.  Very fortunately, no persons were injured.  Property damage is estimated at $16,000.

Leprino Foods is a cheese and whey facility and began its operations in Greeley on October 31, 2011. The plant employs about 100 people and processes more than 700,000 pounds of cheese each day in the portion of the building that is complete, which is approximately 500,000 square feet. The remainder of the building, which will ultimately encompass 880,000 square feet, is still under construction.

Look for a future blog post detailing lessons learned from fire safety issues that occur in contractor sheds and construction work areas.