Dueling Logics of Delay: Chemical Complexity and Institutional Responsiveness in EPA New Chemical Reviews

• In Event: Regulating the Environment in China and the US: Complexity, Monitoring, and Frameworks

Abstract

This study investigates the dynamics shaping efficiency of new chemical review process under the U.S. Environmental Protection Agency (EPA) implemented through the Toxic Substances Control Act (TSCA). Through the construction and empirical analysis of a structured dataset reviewed between 2016 and 2024, this study evaluates whether regulatory efficiency—defined here as timely and risk-proportional decision-making—is primarily governed by the scientific complexity of the chemical (endogenous factors) or by institutional responsiveness and administrative context (exogenous factors). Building on regulatory governance theory and science-policy co-production frameworks, the study models the EPA’s decision logic as a latent function g(A,B), where A denotes chemical risk profiles and B denotes temporal-institutional proxies (start and end year of review). Using a supervised machine learning approach—specifically, Random Forest classifiers interpreted through SHAP (SHapley Additive exPlanations)—the paper identifies and compares the predictive weight of factors that determine whether a chemical review exceeds statutory deadlines. Results show that while certain risk profiles of chemical cases consistently emerge as the top predictor of prolonged reviews, institutional markers also exert strong influence suggesting that regulatory outcomes are co-shaped by internal scientific logic and external institutional dynamics at different stages of the chemical review process. These findings challenge the presumption of purely science-based efficiency in TSCA implementation, instead revealing a “dueling logic” wherein technical risk evaluation interacts with administrative volatility. The study contributes to scholarship on regulatory legitimacy by demonstrating that review durations—while ostensibly a technical outcome—function as institutional signals shaped by policy, procedural, and epistemic currents. These findings have implications for restoring stakeholder trust through more transparent, risk-aligned, and context-resilient review structures.

Authors

• Kalim Shah, University of Delaware
  Presenting Author

• Aditi Chaturvedi, University of Delaware
  Non-Presenting Co-Author