There have been a number of interesting news stories (here, here and here for instance) about an explosion and resulting fires at a Southern California waste treatment facility, Southern California Waste Water. It seems that a vacuum truck delivering what was supposed to be non-hazardous waste exploded at the site, spewing an as of yet unidentified chemical mixture on site that ignited various organic materials (including tires of a fire engine and boots of fire fighters; how ironic) on site.
Looking at the company’s web site it looks like they take in wastes from a variety of customers across the Southern California, de-water the material and prepare a solid material that can be used as a daily cover in selected solid waste disposal facilities. This is a somewhat unattractive, unexciting (on most occasions) and very necessary side of the chemical industry. The company relies on its customers to properly characterize the waste streams that are picked up by various trucking companies specializing in non-hazardous waste hauling.
The vacuum truck goes out to a customer facility and sucks up the waste material from treatment ponds, storage tanks and the like and then delivers it to the SCWW facility. From photographs from the various news articles it appears that the solids in the waste are separated from the bulk of the water (which then is probably sent to a water treatment works). The solids are then combined with other material to form a material that can be used to cover other debris and trash at a landfill.
What apparently happened on Tuesday morning was that a large vacuum truck pulled into the facility that contained some material that was reacting chemically within the truck. We don’t know yet what the material was but it seems obvious from the pictures that some sort of gas and maybe heat was being generated by the reaction and the pressure built-up in the tank. While sitting at the facility apparently waiting to unload the pressure built up to the point where the back of the truck flew off and sprayed the contents all over the facility.
As the material dried in contact with air it formed a material that would ignite organic material that it came in contact with; organic materials like plastic, rubber or wood. From the news stories and photos it would seem that a fire truck pulled up on the scene, rolled into the liquid spill and at some point the tires caught on fire as did the boots of some of the fire fighters.
Not know fully what chemicals were involved, and having a river nearby where any fire-fighting run-off would go, the fire departments involved decided not to fight the various fires that sprung up on site and concentrate of confining the incident to the facility.
There was a relatively minor injury to a truck driver from the initial explosion (I don’t really like that term in this context as it does not appear there was any fire involved initially, just a pressure build up and catastrophic failure of containment), but there are no real reports of serious chemical injuries on the scene.
Unfortunately, there were some complications at a local emergency room. Some people from the site showed up at the ER complaining about chemical exposure issues. Since they were apparently self-transported they were not decontaminated before arriving at the ER. As a result news reports indicate that there were 12 ER employees that were treated for ‘respiratory distress’. Since we don’t yet know what chemicals were involved these may have been caused by chemical exposure reactions or just a very typical and understandable psychological reaction of people to an unknown and unpleasant odor associated with a potential chemical hazard.
This points out a problem that all ER’s must prepare for when there is an incident at a nearby chemical facility. While we expect the local hazmat team and ambulance teams to ensure that transported individuals are decontaminated before leaving the scene, people that self-transport are usually not so careful. It would be a good idea to set up a triage area outside with decontamination equipment and appropriate PPE for the decon team to avoid contaminating the ER when a chemical incident takes place in the local area.
The investigation into this incident is on-going with local agencies, the EPA and OSHA probably being involved. Since there were no deaths or serious injuries reported to date, it is unlikely that the Chemical Safety Board will be involved.
A major focus of the investigation will certainly be the facility from which the truck load of waste originated. Also sure to be looked at will be the clean out procedure used on that truck before the last load was picked up to see if cross contamination of waste streams may have been the culprit.