Home Hot Wash THMG179 – Hot Wash: Paraquat Dichloride

THMG179 – Hot Wash: Paraquat Dichloride


In this hot wash episode, Bob and Mike discuss a chemical they’d previously never heard of – paraquat dichloride.

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Complete Show Notes

1:45 Introduction to the Anonymous Listener

  • Captain with a moderate-sized fire department in the South – fourth largest in the state
  • Been involved with hazmat for over 20 years
  • Started on a federal response team before getting into a fire department
  • Works for 3-4 private contractors on his days off and teaches within the state system

4:20 Background on the Situation

  • This run was as a private contractor, not with the fire department
  • Called out to a large shipping company to do a tote-to-tote transfer
  • Originally told 35 gallons had leaked and they just needed transfer and cleanup
  • Overwhelmed with a stench from the trailer as soon as they opened the doors
  • Quickly realized it was much more than 35 gallons – more like 125 gallons (or half the tote)
  • Pulled up MSDS – first thing it said was “toxic” and said paraquat dichloride, which is a defoliant herbicide
  • Googled paraquat dichloride because he didn’t recognize the name – first result was an EPA warning about it
  • Couldn’t find anything in the NIOSH or much in general, which was odd
  • Learned the pH was 5 and that it had a low vapor pressure
  • Saw a greenish-blue liquid all over the trailer, so he closed the doors and went around to the loading dock side
  • Entire parking lot was also blue green – dropped some pH paper into it
  • MSDS says you shouldn’t let it get into waterways or runoff, so they knew they were in a bad situation when it started raining – were able to block the storm drain, which slowed it down somewhat

17:30 Dealing with the Parking Lot

  • This product sticks around for a long time – anything used to clean the spill up should be removed and shipped accordingly
  • Considering getting a vac truck on-scene, but there was also concern that the pH of 5 would be detrimental to the tanker
  • Cost is a big factor when dealing with the private sector – much more than with municipal fire departments
  • Most private contractors have PID, pH paper, and other supplies – they still have to address minimum OSHA standards

22:50 Signs and Symptoms

  • Signs and symptoms might not show up from 5-15
  • Causes fibrous materials to form in your lungs and gastrointestinal system
  • Passes transdermally very easily since it’s so soluble in water
  • Read that in other countries, some people drink this to commit suicide
  • Homeowners can’t buy this in the United States – strictly for licensed applicators

24:35 PPE Selection

  • Vapor pressure in PubChem is .0000001%, so Bob would be comfortable with Level B
  • Most important thing is just keeping yourself clean
  • Overpacking would be difficult since it’s corrosive to metals

28:30 Takeaways from the Run

  • Know your limitations and understand whether it’s a local contractor or a hazmat team
  • You want to be able to fix the problem on your own, but it’s important to realize when an incident is beyond your scope
  • Take a moment to see what’s going on – what’s the product, what’s the proper PPE, etc.

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