The Hazardous Materials Regulations (HMR) of the US DOT found at 49 CFR Parts 171-180 regulate the transportation of all hazardous materials in commerce.  A material or substance is determined to be hazardous if it poses an unreasonable risk to health, safety, and property when transported in commerce.  Some hazardous materials are determined by the US DOT to pose too great a risk for some modes of transportation:  passenger air/rail or cargo air; and others are banned from transportation in commerce altogether, these are the “Forbidden” Materials.

If you are a Shipper of a hazardous material (HazMat) you are responsible for its classification before offering it for transportation to a Carrier.  The identification of a “Forbidden” Material is an important part of that classification.  If you are a Carrier, you should be aware of “Forbidden” Materials and know what to look for when accepting shipments for transportation; the transportation in commerce of a “Forbidden” Material could result in a catastrophic HazMat incident which you do not want to be involved in, no matter who is at fault.  The purpose of this article is to explain how the HMR identifies a “Forbidden” Material and your responsibilities as a Shipper or Carrier.

The following materials are identified as Forbidden by the US DOT at 49 CFR 173.21 unless otherwise provided in the HMR:

• Materials designated as “Forbidden” in column 3 of the Hazardous Materials Table at §172.101.
• Forbidden explosives defined at §173.54.
• Electrical devices (eg. batteries), which are likely to create sparks or generate heat, unless packaged to prevent such an occurrence.
• A package with a specified magnetic field if to be transported by aircraft [§173.21(e)].
• If packaged with another material (same packaging, freight container, or overpack) when the mixing of the two could create a hazard [§173.21(f)].
• A package with a specified Self-Accelerated Decomposition Temperature (SADT) or a specified polymerization temperature if there will be an evolution of a dangerous quantity of heat or gas [§173.21(f)].  This paragraph goes on to describe in depth the specific conditions that apply to this description.  I encourage you to read this closely if it may apply to your operations at all.
• Packages with a material that is not Forbidden that give off a flammable gas or vapor likely to create a flammable mixture with air in a transport vehicle.
• Packages with a material (not classified as explosive) that will detonate in a fire.
• A lighter as defined at §171.8 containing a Division 2.1 Flammable Gas or Class 3 Flammable Liquid unless it is of a design that is allowed by regulation or by the US DOT [§173.21(i)].
• The “Ketone Peroxide” category of an organic peroxide calculated per §173.128(a)(4)(ii) to contain >9% available oxygen [§173.21(j)].  It includes but is not limited to:
  • Acetyl acetone peroxide
  • Cyclohexanone peroxide(s)
  • Diacetone alcohol peroxides
  • Methylcyclohexanone peroxide(s)
  • Methyl ethyl ketone peroxide(s)
  • Methyl isobutyl ketone peroxide(s)
• An oxygen generator (chemical) as cargo in a passenger aircraft even if identified as acceptable elsewhere in the HMR.  However, an oxygen generator for a passenger’s personal or medical needs that meets the  requirements of §175.10(a)(7) is not a “Forbidden” Material.

Be aware that some hazardous materials are listed in the Hazardous Materials Table and then identified as “Forbidden” in column 3 (eg. Galactsan Trinitrate).  Refer to this PHMSA/USDOT website with a list of hazardous materials identified as Forbidden in column 3 of the Hazardous Materials Table:  Forbidden Materials (September 25, 2000).

Others may only be forbidden by a specific mode of transportation, but otherwise acceptable for transportation in commerce, examples:

• Hydrogen, compressed:  Forbidden for transportation by passenger air or rail (column 9A of the Hazardous Materials Table).
• Hydrogen Sulfide:  Forbidden for transportation by passenger air or rail (column 9A of the Hazardous Materials Table) and cargo air (column 9B).

So, what can you do with a “Forbidden” Material if you cannot transport it?  If offsite transportation is necessary, you have two options:

• Change the material or package in some so that it no longer exhibits the characteristic of a “Forbidden” Material.
• Apply for a Special Permit from the US DOT.

“Forbidden” Materials are one of those aspects that may never affect your operations under the HMR.  Or, it may be a significant factor in how you prepare for transportation or transport a hazardous material.  My training will teach you how to determine which of the regulations apply to you and what you must do to maintain compliance.  Please don’t hesitate to contact me with questions.