Due to Anhydrous Ammonia (ammonia, anhydrous) having both international and domestic entries in the Hazardous Materials Table (HMT)(See 49 CFR § 172.101), considerations must be made in order to determine the need for a Hazardous Materials Safety Permit (HMSP):

• For Anhydrous Ammonia in “domestic transportation” (See 49 CFR § 171.8)  and described as UN1005 ammonia, anhydrous 2.2 Inhalation Hazard, an HMSP is not required.
• For Anhydrous Ammonia described as UN1005, ammonia, anhydrous 2.3 Poison Inhalation Hazard or Toxic Inhalation Hazard, Zone D, and when transported in a packaging having a capacity greater than 13,248 L (3,500 gallons), an HMSP is required.  In these instances, Anhydrous Ammonia meets the definition of a Material that is Poison-By-Inhalation or Toxic-By-Inhalation as defined in 49 CFR § 171.8 and meets the criteria for a hazard zone D as specified in 49 CFR § 173.116(a).

Last Updated : August 29, 2017