EPA Holds Webinar on Biofuel PMNs: New Chemical Risk Assessment and Applications of the Tools and Mo

By Lynn L. Bergeson and Carla N. Hutton

On March 23, 2022, the U.S. Environmental Protection Agency (EPA) held a webinar on “Biofuel Premanufacture Notices: New Chemical Risk Assessment and Applications of Tools and Models.” As reported in our January 24, 2022, blog item, in January 2022, EPA announced an effort to streamline the review of new biobased or waste-derived chemicals that could displace current, higher greenhouse gas (GHG)-emitting transportation fuels. EPA states that to support this effort, it is offering outreach and training to stakeholders interested in biofuels. According to EPA, the bi-weekly webinar series includes reviewing requirements under the Toxic Substances Control Act (TSCA), outlining the streamlined approaches for risk assessments and risk management actions, and providing information on how to navigate the new chemicals premanufacture notice (PMN) process. EPA provided background and outlined the following challenges for each risk assessment conducted:

• Chemistry Assessment:
  • Fuel stream and related substances are broad in number and scope, especially with the addition of current biobased and waste feedstock blends; they can be class 1, class 2, or chemical substances of unknown or variable composition, complex reaction products, and biological materials (UVCB) substances;
  • Many petroleum-derived fuel streams are on the original TSCA Inventory and there are very little data associated with them; and
  • Complete characterization of the new chemical substance is often unavailable;
• Environmental Fate and Transport Assessment:
  • Analysis of constituents may not represent the properties of the new chemical substance;
• Engineering Assessment: Environmental Releases:
  • EPA’s release assessment analyzes each manufacturing, processing, and use operation and determines the sources/activities that can result in releases to the environment. These release estimates are used to estimate exposure estimates for ecological and human receptors;
  • Examples of release data: (1) Measured release data; (2) Measured release data for a “surrogate” chemical; (3) Modeled release estimates; and
  • Release estimates have limitations — examples:
    • Lack of appropriate model/method to estimate releases from specific industrial activities (e.g., storage tank emissions); and
    • Limitation in certain release models (e.g., limited to a vapor pressure threshold of 35 torr);
• Engineering Assessment: Occupational Exposures:
  • The occupational exposure assessment estimates the magnitude, frequency, and duration of exposures to the new chemical substance at the workplace;
  • Worker inhalation and dermal exposures are expected throughout the lifecycle of the new chemical substance (e.g., manufacturing, processing, use); and
  • Exposure models do not account for some engineering controls (vapor capture/reduction);
• Exposure Assessment: General Population and Consumer Exposures:
  • The occupational exposure assessment estimates the magnitude, frequency, and duration of exposures to the new chemical substance for the general population and consumers via inhalation and drinking water pathways; and
  • The confidence of the exposure estimates are affected by:
    • Assumptions, limitations, and areas of uncertainty in the fate and engineering analyses; and
    • Inherent uncertainties of the exposure parameters and assumptions for the estimation of the general population and consumer exposures;
• Hazard Assessment:
  • Data on the new chemical substance or an analogous biofuel are preferred, but few submissions include toxicological or composition data;
  • EPA often lacks acute/chronic environmental test data on the new chemical substance and the analogous substances; and
  • There are challenges in performing read-across approaches and route-to-route extrapolations with analogous substances of variable composition.

For biofuel PMNs, EPA has started generating one report that combines the results of each of the above assessments. The final webinar in the series will be held April 6, 2022, on new chemicals risk management actions, including TSCA Section 5 orders and significant new use rules (SNUR).