This bill amends the Environmental Research, Development, and Demonstration Authorization Act of 1978 to significantly alter how the Environmental Protection Agency (EPA) conducts chemical toxicity assessments. Its primary purpose is to transfer the responsibility for hazard identification and dose-response assessments, previously handled by the Integrated Risk Information System (IRIS) program, to the relevant program offices within the EPA. These offices, such as the Office of Water or the Office of Chemical Safety and Pollution Prevention, will now conduct these "covered assessments" if they determine a need exists. The bill mandates that these assessments must adhere to new, rigorous scientific standards, emphasizing the use of the best available science and the weight of the scientific evidence . When assigning toxicity values, program offices must include a range of point estimates of risk, along with sources and magnitudes of uncertainty, considering all available datasets. A new chemical assessment database , maintained by the Office of Research and Development, will store these toxicity values, incorporating all existing IRIS assessments. To ensure coordination and prevent duplication of effort, the bill establishes a Hazard Identification and Dose-Response Steering Committee . This committee, chaired by the Assistant Administrator of the Office of Research and Development and comprising EPA employees, will oversee the conduct of assessments and consider qualifying third-party scientific evaluations. Furthermore, the Office of Research and Development will be required to submit biennial certifications to Congress, confirming that all completed assessments meet the specified scientific standards.