Today in Omaha, NE there was an industrial accident at a business where one would expect to find combustible dusts. The accident resulted in several employees being treated for burns and there are two confirmed fatalities as of this evening. And although, we were quick to point out this accident may have involved a combustible dust explosion I now believe that the collapse of the structure was the initiating event and any fires and explosions were secondary to the collapse. Bear in mind this is a THEORY based solely on photographic evidence from OUTSIDE the facility; however, these photographs provide very strong evidence to back up my theory. Using my cause and origin investigation skills from way back in the day I can see (and NOT see) the following using the aerial photos provided by the Omaha Herald (http://odc.omaha.com/index.php?u_page=5002&p=5039)
- OFD states there was smoke upon their arrival and we have video of OFD using one small handline during their response. In other words we have little evidence of major fire damage.
- Photos #1 and 12 at the above link looks like NO OTHER dust explosion scene I have ever investigated. Structure walls most still intact and the walls that are not intact show little to no evidence of a fire or blast.
- Photos #1 and 12 at the link above shows the structure still in tact, but collapsed into the building. Notice the roof is fully intact except where the bucket elevator collapsed. The portions of the roof around the bucket elevator are sagging inward and show no signs of fire/smoke.
- The building sections involved have metal siding which is still fully intact, except the one section directly impacted by the collapse and that section shows very little signs of an explosion and very slight smoke damage, which by all accords could have been caused from the fire(s) after the initial incident.
- All of the damage in all of the photos is either inward or to the shell of the building. We see no debris any considerable distance from the building.
- And the biggest indication this was NOT a dust explosion is the all of the dust collection equipment is still fully intact, as cn be seen in many of the photos in the link above. Dust explosions travel via their source and had this been a dust explosion, most likely we would have seen damage to the dust handling equipment. Had the dust explosion occured outside this type of equipment we would be seeing much more evidence of a blast/fire.
So for us to consider a dust explosion as the initiating event we would be seeing something entirely different from these photos. If the initiating explosion was of such a force that it brought down the bucket elevator then an explosion of that magnitude would have had a pressure wave that would have blown the roof and walls outward. At this stage, based 100% on mere observation of the aerial and ground photos from OUTSIDE the facility my investigation would be leading me to bring in a structural engineer to examine the structure’s load bearing members. There are a multitude of causes that could have caused a structural collapse, from a forklift striking a load bearing member to exceeding the structure’s strength. There were reports of 35-40 mph winds with higher gusts around the time of the accident or shortly thereafter – something to consider with the size of the structure. There could have also been work being done on the structure that could have weakened it. There are just too many potential causes of a structural collapse to even begin discussing at this point.
I would not rule out a dust explosion by any means, but based on what photographic evidence I have seen I would be going down the path of a structural collapse that led to secondary fire(s) and explosion(s). There is just not enough overpressure damage to say this collapse was caused by a dust explosion; but there is some indication that the collapse may have lead to a combustible dust fire and maybe a secondary dust explosion. Just not an explosion of such magnitude that would bring down the structure.