Written on: August 1, 2025 by Nicholas Georges
On July 1, the Pipeline & Hazardous Materials Safety Administration (PHMSA) proposedi to update the definition of an aerosol in the Hazardous Materials Regulations (HMR) to align with international transportation standards. Assuming there are no technical errors with the proposed definition, this is a welcome development for Industry in reducing regulatory burdens.
In the 49 CFR 171.8 (Definitions), an aerosol is defined as “an article consisting of any non-refillable receptacle containing a gas compressed, liquefied or dissolved under pressure, the sole purpose of which is to expel a nonpoisonous (other than a Division 6.1 Packaging Group III Material) liquid, paste or powder and fitted with a self-closing release device allowing the contents to be ejected by the gas.”
Notably, this definition excludes gas-only aerosol products. While aerosols are more heavily regulated than other product types used by consumers and workers, they do qualify for the limited quantity exemption.ii This exemption reduces the cost and legal obligations to ship small quantities of dangerous goods; however, gas-only aerosol products are not eligible unless they are packaged in containers with fewer than four fluid ounces capacity (7.22 cubic inches or fewer).iii
Thus, gas-only products are frequently shipped utilizing a special permitiv to ease certain regulatory requirements, similar to the shipments of other aerosol products. However, the use of special permits requires additional training and recordkeeping, which can discourage some members of the supply chain from handling such products.
Eight years ago, in response to the additional obligations, the Household & Commercial Products Association (HCPA, formerly the Consumer Specialty Products Association), the Council on Safe Transportation of Hazardous Articles Inc. (COSTHA), the National Aerosol Association (NAA) and the American Coatings Association (ACA) petitioned PHMSA to revise the HMR’s definition of an aerosol. Since the HMR’s definition is inconsistent with international counterparts, gas-only aerosol products are at a disadvantage in the U.S. This lack of harmonization between the HMR and international standards causes challenges for industry stakeholders engaged in global commerce, leading to confusion, increased compliance costs and logistical inefficiencies. The inconsistency also impacts trade, delays shipments and reduces the competitiveness of U.S. businesses in the global marketplace.
PHMSA’s current proposal aims to align the definition of an aerosol with international standards, including the United Nations Model Regulations (UNMR), the International Maritime Dangerous Goods (IMDG) Code, the International Civil Aviation Organization Technical Instructions on the Safe Transport of Dangerous Goods by Air (ICAO TI), and the Regulations governing European Road Transport (ADR). The proposal defines aerosols as “an article consisting of a non-refillable receptacle, containing a gas (compressed, liquefied or dissolved under pressure), with or without a nonpoisonous (other than a Division 6.1 Packaging Group III material) liquid, paste or powder, and fitted with a self-closing release device allowing the contents to be ejected as a foam, paste or powder or in a liquid state or in a gaseous state.”
If finalized, gas-only aerosol products would ship the same way as other aerosol products in the U.S. The proposal would ease the regulatory obligations required by a special permit, lessen barriers to trade and, ultimately, benefit consumers by enabling more effective shipping of these products and reducing costs in a competitive marketplace.
HCPA is in the process of conducting a complete review of the proposal to ensure that there are no technical errors or challenges. Assuming there are none, HCPA will submit a letter in support of this action by the Sept. 2, 2025, deadline and asks aerosol companies to do the same—using a letter template provided by HCPA. This will help ensure the proposal is finalized.
Thank you to everyone who has been involved in supporting the alignment of the definition of an aerosol with international standards over the last eight years. While this is a great achievement, the aerosol products industry must continue its efforts in securing regulatory relief for the transport of aerosol products. These efforts are mostly focused on the modernization of regulations found in the HMR, such as the construction requirements of aerosol containers, alternatives to the waterbath test and making it easier to ship “waste” aerosols that are destined for recycling.
For more information or to get involved with any of these activities, please contact me at ngeorges@thehcpa.org. SPRAY
i link
ii 49 CFR 173.306
iii 49 CFR 173.306(a)(1)
iv Examples include DOT-SP 10232, DOT-SP 10704, and DOT-SP 11516
