In this episode, Mike talks to Stephen McManus about a few of the more memorable hydrofluoric acid incidents he’s been involved with.
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Complete Show Notes
3:10 Introduction to Stephen McManus
- Career firefighter who also did a stint in the industrial side as a career chief for an industrial fire department
- Also worked as a volunteer firefighter over the years
3:40 Working on a High-Hazard Team
- Worked on a high-hazard team in the 90s that traveled around the world working for different governments
- In one case, they were working in a facility that had been abandoned for 20 years – contained a 55-gallon drum of hydrofluoric acid
- Room also contained uranium hexafluoride and a number of other different chemicals – this potentially-enriched uranium added another twist and added the potential for an explosion
- Room was only 5 x 5 or 5 x 8 – drum was so rusted and damaged that they were worried about a rupture
- Posed a criticality issue – this facility had been involved with weapons, and the enriched uranium made things even more dangerous
- Bladder was holding everything inside the drum – everything else was so rusted you could have stuck a pencil through it
- Took a lot of different people from various backgrounds to design a plan to safely go in and do the necessary work
- Team worked in Level A suits and used peristaltic pumps to transfer the acid safely into another tank in the same room
- Peristaltic pumps allow you to create a suction without running the product through the pump itself
- Uses compressed tubing that goes around the pumping mechanism
- Tubing is disposed of afterwards since it’s contaminated and basically destroyed
- A pinhole formed on the tubing as they were making the transfer, which allowed hydrofluoric acid to escape into the room – luckily, they were prepared for almost any kind of leak
- Vapors from escaped hydrofluoric acid started to eat camera lens in the camera used by one of the agencies watching the high hazard team
- Went through a whopping 12 Level A suits during the 3 days of working on the operation – were able to deal with everything in the room, though
- Level A suits were the main limiting issues for the team, but they chose this level of protection due to their work-ups and the safety information they’d gathered
- Did wet decon with a few chemical mixtures based on the potential of not having any contamination due to coming into contact with hydrofluoric acid – were more concerned with getting the person out than saving the suit
21:15 Dealing with Buried Cylinders
- Had to deal with hundreds of stacked cylinders that contained a wide variety of mixed gasses – specially designed with valving on both ends
- None of these chemicals should have been mixed together – dealing with them was very dangerous for the team
- Had to drill into the cylinder, remove the product, and run it through a scrubber system
- One of the cylinders contained hydrofluoric acid mixed with another dangerous gas – ended up reacting with the scrubbing unit
- Scrubber started to dance around on the floor even though it weighed 400-500 pounds – also spewed black liquid from one of the charcoal systems
- Had to deal with shutting the scrubbers down while also handling the product in the scrubbers and continuing to contain the hydrofluoric acid
- Luckily, it was a smaller cylinder, so there wasn’t as much product to deal with
- Used a collar system that could be fitted onto any cylinder and helped create a valve as you drilled into the cylinder
- Existing valving was bad on the cylinder itself, so the collar system formed a vacuum around the bad valving – this became the valve that you could pull product through
- Wore Level A protection since there were toxicity concerns along with fire and explosion potential
32:30 Assessing Hydrofluoric Acid Cylinders
- Handle this essentially the same way you’d analyze and assess any cylinder
- Analyze the integrity of the body – how much damage has been done by rust or otherwise?
- Has it been physically damaged? Are there any gouges or cuts?
- Does the valving and threading appear to have leaked at any time?
- Is the metal of the valving still intact? Are there any stress fractures?
- Has it been subjected to any thermal damage (i.e. fire)?
- Has it leaked?
- Use pH wipes on the outside to determine whether there’s any type of reaction with the metal
34:05 Dealing with Leaking Pipes
- In one case, leaky pipes were spraying hydrofluoric acid across a staircase they needed to use to get to an area where they could mitigate the problem
- Had to devise a shield system to keep the pinstream leak of hydrofluoric acid from getting onto the responders
- Team was able to close a valve off to stop the actual leak in the pipe – had to catch runoff from the pipe while also dealing with vaporized hydrofluoric acid
- Stephen’s team stopped the leak, offloaded the leaking tank, and vented the room
- Another team came in to do the final cleaning and neutralize the hydrofluoric acid that had gotten into the concrete – room was condemned and wouldn’t be used again
41:00 Stephen’s Biggest Tips for Responding to Hydrofluoric Acid Incidents
- Always know your risk and make sure you’re dealing with the product you think you are
- Stay alert of what other substances are in the area
- Assess how bad the leak is – applies for both liquid and gaseous hydrofluoric acid
- If you’re dealing with a gas leak, know what’s in any nearby containers – you could be dealing with a potential reaction
- Know whether there’s potential for a catastrophic failure for the vessel you’re dealing with and/or if the leak could cause catastrophic failure to another vessel
- Think about how far your recon team is going to explore – how big is your scene survey?
- Make sure local hospitals and on-site medical staff are prepared to deal with hydrofluoric acid exposure
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- THMG147 – Hydrofluoric Acid Series, Part I: Introductions
- THMG063 – Top 5 Chemicals That Will Hurt You
- THMG067 – Acid/Base Titration