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Hey! What’s on That Truck? Identification of Hazardous Materials in Transportation

Hey! What’s on That Truck? Identification of Hazardous Materials in Transportation

One thing about hazardous materials that can’t be denied is that they move among us all the time.  It’s the proximity of hazardous materials in commerce to people that makes adherence to the Hazardous Materials Regulations so important.  Since we find hazardous materials in transportation around us frequently, it behooves us to learn more about them and the hazard communication methods.  Take a look at the photo below and see if you agree with my interpretation of the regulations.

Tanker truck of Sodium Hydroxide Solution

Do you know what this truck is hauling? Do you know how to find out?

Despite commonly being referred to as a tanker truck, the vehicle in the picture is defined by regulation at 49 CFR 171.8 as a cargo tank motor vehicle.  The cargo tank, permanently attached to or forming an integral part of the motor vehicle, also meets the definition of a bulk packaging (ie. >119 gallons for a liquid).  This is important because both bulk packagings and motor vehicles have specific placarding and marking requirements in the Hazardous Material Regulations (HMR).

To identify the HazMat contents of this cargo tank, I’ll start with the placard.  A motor vehicle carrying a bulk packaging of a hazardous material must be placarded on each side and each end (ie. all four sides) as is this truck.  The placards displayed are those for a Class 8 Corrosive Material.  The requirements for the appearance of a Class 8 placard can be found at §172.558, while a Corrosive Material is defined at 49 CFR 173.136.  A Class 8 Corrosive Material can be summed up as:

  • A liquid or solid that causes full thickness destruction of human skin at the site of contact within a specified period of time.


  • A liquid, or a solid which may become liquid during transportation, that has a severe corrosion rate on steel or aluminum.

I’ll assume that the contents of this cargo tank are a liquid.  So at this point we know we’re talking about ~5,000 gallons of a Class 8 Corrosive Liquid.

Next, notice the four numbers in the middle of the placard:  1824.  This is the identification number for the hazardous material.  Used in other forms of hazard communication – as part of the basic description on the shipping paper and as a marking on a non-bulk packaging- the four digits are preceded by either a “UN” for United Nations or “NA” for North America.  On this bulk packaging the two letter prefix is dropped leaving just the four digit identification number.  Interestingly, the display of the identification number on the placard is just one available option, §172.332 identifies three options for display of the identification number on a bulk packaging:

  1. On an orange panel near the placard.
  2. On the placard, as in this case.
  3. On a white square on point marking near the placard.

It is the identification number that will help us get a more specific answer to our question, “What is it?”.  The identification number of 1824 corresponds solely to the proper shipping name for:  Sodium Hydroxide Solution.

So, what we have here is a cargo tank with a capacity of approximately 5,000 gallons displaying hazard class 8 corrosive material placards and the identification number for Sodium Hydroxide Solution.

One more question:  Is the cargo tank full? Or does it merely contain the residue of a previous shipment?  That one is impossible to answer from this picture since §172.302 and §172.514 require the continued use of markings and placards unless the bulk packaging is rinsed clean and purged of all vapors.  So, it’s possible that this cargo tank has been emptied and contains only residue of the initial HazMat.

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Keep your eyes open while on the road or in a truck stop.  Snap a picture if you can do so safely and if the driver doesn’t mind.  Send it to me and I’ll tell you what I know.  Drive safe and don’t hesitate to contact me with any questions.