In this episode, Mike runs through a hotwash based on a listener-submitted sodium hydrosulfite incident.
Complete Show Notes
1:20 What is a Hotwash?
- Immediate after-action discussions and evaluations of an agency’s performance following an exercise, training session, or major event
- Designed to identify strengths and weaknesses – intended to guide future responses to avoid repeating errors made in the past
- Bob & Mike want to establish an audio archive of events that have taken place to be passed down from one generation to the next
- Anybody can submit a hotwash, and you don’t have to reveal any identifying information about yourself or be on the show
3:05 Dispatch Information
- Time: 7 AM
- Weather cool and unremarkable
- Dispatch reports that fumes are coming from a drum
- Hazmat unit is 15 minutes away – by the time they arrived, they were around 25 minutes into the incident
4:00 Information Received En Route
- Received via radio transmission
- Confirms that some kind of gas under pressure is leaking from a drum
- Transmission was a little unclear, but thought they heard the word “Dirtex”
- First arriving units are detecting hydrogen sulfide gas
- Resource officer looks up Dirtex with gathers the following information from its SDS:
- Cleaning powder
- Non-flammable – product of combustion with CO and CO2
- This is interesting because the units were only detecting H2
- There was no report of the product being involved with fire
- Ingredients:
- Sodium sesquicarbonate
- Sodium metasilicate
- EDTA
- Tetrasodium
- None of these ingredients really fit into the puzzle, and a discussion breaks out due to the presence of H2
- Started a cross-sensitivity check to see if any of the products of combustion or a reaction might cause the H2 sensor to go off
8:20 Making Entry On-Scene
- Entry team does an initial hazmat recon in bunker gear and SCBA since the situation isn’t making much sense
- They see a 30-gallon drum against the wall that’s rusty and has debris piled on top of it
- They also see liquid on the rim and on the floor around the drum
- Some kind of gas is pushing out under pressure from the top of the drum where the rust has eaten away the lid
- Pressure in the drum wasn’t building, and there are no other signs of stress
10:30 Metering and Reading Labels
- High levels of H2S, but it was sticking around – affecting people within a quarter mile of the drum
- Normal O2 – no reading of CO, LEL, or VOC
- Thermal imaging showed the drum was hot – maximum temperature reading of 170 degrees Fahrenheit
- No pH in the atmosphere
- Labeling
- Detailed inspection of the drum showed a label with the following information:
- CAS number
- Company name with a phone number
- Warning label that said: “Water-reactive and will release H2S”
- LD50 indicated that the product was a solid
- Also supported the meter’s H2S readings and reinforced the possibility of a sudden reaction
- At that time, the resource officer learned that it was a 30-year-old drum that was never used – the representative from the company didn’t have any other information
- Detailed inspection of the drum showed a label with the following information:
14:10 Identification
- Based on the CAS number, they determined that the chemical was sodium hydrosulfite
- SDS provided the following information:
- Combustible – decomposes with an SSDT of 190 F
- Slightly alkaline
- Shelf life
- Chemical name was actually Virtex – not Dirtex
- All of this information confirmed the information on the drum
- At this point, the team feels certain that they’re definitely dealing with sodium hydrosulfite
- The drum has stopped producing gas under pressure, and second entry determines that the temperature had also started to come down
17:50 Briefing with Incident Commander
- Incident commander (IC) wants to know what your options are
- Based on the SDS information and observations, entry- and senior-level personnel on the team provide two choices:
- Option 1: Do nothing – monitor and allow the product in the drum to safely complete its reaction
- IC isn’t a fan of this because it would take a lot of time – a few blocks in the vicinity had already been closed off
- Option 2: Remove product from drum and lay in a pop-up pool filled with water
- Felt that although it was water-reactive, the large amount of water would pull heat from the reaction, allowing it to pass quickly
- This would also cause it to produce large quantities of by-product rather quickly
- IC seemed to prefer this method
- Option 1: Do nothing – monitor and allow the product in the drum to safely complete its reaction
20:20 Gathering More Information
- Attempted to call the company whose name was on the label, but discovered they’re no longer in operation
- At this point, they decided to call Chemtrac – determined the situation was beyond their capabilities and referred the resource officer to Chemtrade
- Chemtrade found a contractor in Texas who knew the chemical and was able to provide advice on how to handle the situation – his advice matched what the team was already planning on doing
- Chemtrade then found an employee from a company who made the product and spoke with him
- Contractor said that once the reaction was complete, you’re left with a bleach-like solution that can safely be poured down the drain
23:15 Finishing the Reaction
- Armed with this information, the team moved forward with pushing the reaction to completion
- Filled their pop-up pool with water and started to put the chemical into the pool
- They did this because putting small amounts of the chemical in water allowed the heat of the reaction to be absorbed
- This also allowed them to stop the process in case something went wrong unexpectedly
- When they finished the operation, they noticed there wasn’t much of a reaction at all
- Between the reaction that had occurred and the age of the chemical, the reaction was mostly completed by the time they placed the chemical in the pool
24:25 Lessons
- Constantly compare information for congruency
- Chemtrac and Chemtrade are fantastic resources
- Have an understanding of basic chemistry – you can’t have a sulfide by-product if you don’t have sulfur
- Understand and utilize the resources you have (like SDS sheets)
- Perform the operation in small amounts and increase whenever it seems safe
Have a question? Send an email to feedback@thehazmatguys.com or leave a message on our Haz Mat Guys comment hotline: 843-628-1484
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- THMG003: Toxics, Part I
- THMG064: 6 Tips to Make You a Better Resource Officer
- THMG073: Leaking Tanks 2.0
