Hazmat Compatibility: What Shippers Need to Know

Posted on 10/21/2019 by Roseanne Bottone and Roger Marks

Last week in Tillamook, Oregon, local fire fighters responded to a hazmat incident caused when muriatic acid and chlorine were accidentally mixed at a hotel pool facility—forming chlorine gas. Two employees were admitted to a local emergency room for breathing problems following the incident, and the pool room had to be ventilated.  
Some dangerous chemical mixtures are common knowledge: Many of us know not to mix bleach with ammonia, for example. The mixture produces a chemical reaction to form chloramine vapors and liquid hydrazine. Exposure to the vapors can cause mild to severe respiratory symptoms, including irritation to the throat, nose and eyes; nausea; coughing; shortness of breath; and even death.
Even small amounts of these chemicals mixed together can cause a major hazard. In transportation, the risks can be even greater. Imagine two incompatible chemicals shipped in the same combination packaging or overpack. The packaging fails during transportation and the chemicals mix in the back of a truck. Unbeknownst to the driver, the truck trailer begins filling with toxic gas. When the driver opens the back—during a highway inspection or during delivery—the toxic gas is released and creates a major health hazard for anyone nearby.
When shipping hazardous materials, it is crucial that incompatible materials are kept away from each other. But how do hazmat shippers know which materials will react with others, or with their packaging?  

Compatible With What?

When preparing packages for shipment, there are three main considerations related to compatibility. Your hazardous materials/dangerous goods must not react with:
  1. The parts of packagings with which they are in direct contact. The package should remain durable during the cycle of transportation. Consider corrosivity, permeability, softening, premature aging and embrittlement;
  2. Other materials packed in the same package that could produce heat or vapors; or
  3. Absorbent and cushioning materials.

The Shipper’s Responsibility

Even though packagings are authorized by Proper Shipping Name by the DOT, IATA regulations, or the IMDG code, it is still the shipper’s responsibility to ensure full compliance with all regulations, including compatibility.
Need hazmat training now? The DOT Hazmat Ground Shipper Certification Online Course covers what shippers need to know to classify, name, package, mark, label, load, and document hazmat shipments in full compliance with the 49 CFR Hazardous Materials Regulations (HMR).

Take Care: Plastics, Glass, and Polymer Materials 

Take special care with plastics. Some can be softened, rendered brittle or permeable as a result of temperatures reached because of a chemical reaction with contents or exposure to refrigerants. Appendix B of 49 CFR Part 173 contains a procedure for testing chemical compatibility and rate of permeation in plastic packaging and receptacles.

Glass should not be exposed to fluorine (a toxic gas of the halogen series and the most reactive of all elements). Hydrofluoric acid can eat through glass.
Polymer materials (e.g., polyethylene and polypropylene) are prone to swelling, permeation, chemical degradation, and cracking due to environmental stress.

What About Other Materials?

It is the shipper’s responsibility to ensure incompatible materials or packagings don’t cause combustion or dangerous evolution of heat; the evolution of flammable, toxic, or asphyxiant gases; or the formation of unstable or corrosive materials.
A common question that comes up in Lion’s hazmat workshops is “Where can I get information about compatibility issues?”
Safety Data Sheets (SDS) hold valuable information about the hazards of your material, including compatibility issues to be aware of. In addition to the SDS, you can consult:
Hazmat regulations. Each mode of transportation has separation and segregation rules. The DOT’s segregation of hazardous materials rules are at 49 CFR 177.848. Check the IATA DGR 9.3.2 for incompatible dangerous goods. Chapter 7 in the IMDG Code, and Column 17 on the 3.2 Dangerous Goods List address the same concern.
Other reference materials. Consult references like The Merck Index, the CRC Handbook of Chemistry and Physics, and Perry’s Chemical Engineers’ Handbook.
A web search for the term “chemical compatibility” yields some useful tools, for example, this Fisher-Scientific Chemical Compatibility Chart, made available by the University of Wisconsin. In addition, you can search for information about how chemicals react with packaging materials with search terms like “chemical compatibility with metals” or “chemical compatibility with plastics.”
Laboratory testing. You can also have laboratories test potential packaging material. For example, ASTM D543 evaluates the resistance of plastics to chemical reagents. Search for “chemical testing laboratories.”

By taking time to select appropriate packaging and ensure incompatible materials are properly separated and segregated, hazmat shippers protect employees, supply-chain workers, and the public from the risks of a major chemical incident.  

Complete Multimodal Hazmat Shipper Workshops Near You

All hazmat employees need a solid grasp of the 49 CFR, IATA DGR, and IMDG Code regulations to maintain compliance. Every step of the hazmat shipping process is regulated in some way, and even small mistakes can lead to injuries, emergencies, rejected shipments, and fines that get more expensive every year.  

Join expert Lion instructors for the final Complete Multimodal Hazmat Shipper Certification Workshops to keep your expertise up to date and satisfy DOT, IATA, and IMDG training mandates.  


Oct. 28–31


Oct. 28–31


Dec. 9–12


Dec. 16–19

Save your seat now or view the 2020 schedule here. 

Tags: 49 CFR, compatibility, hazardous materials, hazmat, hazmat shipping

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