EPA Announces New Framework to Assess Eye Irritation in New Chemicals

On January 8, 2024, the U.S. Environmental Protection Agency (EPA) introduced a new framework for identifying eye irritation and corrosion hazards in new chemicals evaluated under the Toxic Substances Control Act (TSCA). This standardized approach aims to enhance transparency and consistency in final risk assessments. The framework aligns with EPA's commitment to reduce animal testing, increase the efficiency of chemical reviews, and expedite market entry while safeguarding human health.

As part of TSCA requirements, EPA must assess new chemicals within 30 or 90 days, identify potential hazards and conduct risk assessments. Evaluation of eye irritation or corrosion is an integral part of this process. Traditionally, animal testing using rabbits was employed for this purpose, but its inconsistency, especially for mild to moderate irritation, has raised concerns about its applicability to humans.

HIGHLIGHT OF THE FRAMEWORK

The new framework is aimed at promoting alternative test methods known as New Approach Methodologies (NAMs). These methods eliminate or reduce testing on vertebrate animals while maintaining scientific rigor in assessing chemical hazards. In addition to promoting ethical practices, the transition to NAMs is expected to save time and money for stakeholders by eliminating the necessity for animal studies.

By emphasizing reproducible data, EPA aims to streamline decision-making by ensuring a standardized process for evaluating eye irritation or corrosion hazards in new chemical test data. It relies on peer-reviewed literature, accepted Organization for Economic Cooperation and Development (OECD) test guidelines, and other recognized risk assessments.

A BRIEF OVERVIEW OF THE FRAMEWORK

• Available data on the chemical substance are evaluated for quality and applicability.
  • Data are prioritized in the following order:
    • Data from human cell or tissue test methods.
    • Data from in-chemico, in vitro, or ex vivo test methods.
    • Data from in vivo test methods.
  • Where data from eye irritation or corrosion tests are not available, test methods that assess skin irritation or corrosion potential may be considered. 
• If eye and skin irritation or corrosion data are not available, other information may be considered. Where no data exists, a hazard determination may not be possible.
• Any relevant human data will be evaluated and incorporated on a case-by-case basis. 

EPA’s New Chemicals Program (NCP) prioritizes the use of methods that use sensitive human cells or tissues to identify non-irritating chemicals, such as OECD TG 492 (1). For the identification of irritating or corrosive chemicals, the NCP favors methods using human cells or tissues capable of assessing the full severity range, such as OECD TG 492B (2), along with reproducible and relevant in chemico, in vitro, or ex vivo methods. The NCP does not recommend the prospective use of the in vivo eye irritation test using live rabbits, such as the Draize test.