The news reports from Farmington Maine are real scary. One firefighter killed and several more seriously injured. A maintenance worker smelled gas and got everybody out in time but the place went up when the fire department was approaching the building to look for a leak. No trace of the building except for the foundation and it took out too nearby mobile homes. One downside to propane is its heavier than air and can collect in low points so a slow leak can build up for hours until it hits the right fuel air ratio and ignition source. The building appears to have been insulated with cellulose so there is cellulose spread around the neighborhood.