Revision to VOC definition includes new exclusion
A final Environmental Protection Agency (EPA) rule revised the regulatory definition of volatile organic compounds (VOC) under the Clean Air Act (CAA) at 40 CFR 51.100(s). This action exempts trans -1,1,1,4,4,4-hexafluorobut-2-ene (also known as HFO-1336mzz(E)). It is now excluded since this compound makes negligible contributions to tropospheric ozone formation.
This rule goes into effect on April 10, 2023. It may affect state and local air pollution control agencies that adopt and implement regulations to control air emissions of VOC; and industries manufacturing and/or using HFO-1336mzz(E) for use in foam blowing, refrigeration, as well as applications in solvents and aerosol propellants. Entities may include among others:
- Industrial gas manufacturing,
- Semiconductor machinery manufacturing,
- Motor vehicle parts manufacturing,
- Boat building, and
- Air-conditioning and warm air heating equipment and commercial and industrial refrigeration equipment manufacturing.
This action will deliver a lower burden on a significant number of small entities. Removing HFO-1336mzz(E) from the regulatory definition, relieves manufacturers, distributors, and users from tropospheric ozone requirements to control emissions of the compound.
EPA believes exempting HFO-1336mzz(E) would not cause a greater risk to human health or the environment. This compound is not regulated as a hazardous air pollutant under title I of the CAA. Furthermore, it is not listed as a toxic chemical under section 313 of the Emergency Planning and Community Right-to-Know Act.
It has been EPA’s policy since 1971 to exempt certain compounds with a negligible level of reactivity from the definition of VOC. They believe that doing this creates an incentive for companies to use negligibly reactive compounds in place of more highly reactive compounds regulated as VOC.
Key to remember: EPA exempted HFO-1336mzz(E) from the regulatory definition of VOC.