Systematic Review Protocol for the IRIS Chloroform Assessment (Inhalation)

The Integrated Risk Information System (IRIS) Program is undertaking a reassessment of the health effects of chloroform via inhalation. IRIS assessments provide high quality, publicly available information on the toxicity of chemicals to which the public might be exposed. These assessments are not regulations, but provide a critical part of the scientific foundation for decisions made in EPA (Environmental Protection Agency) program and regional offices to protect public health. Before beginning an assessment, the IRIS Program consults with EPA program and regional offices to define the scope of the assessment, including the nature of the hazard characterization needed, identification of the most important exposure pathways, and level of detail required to inform program and regional office decisions. Based on the scope, the IRIS Program undertakes problem formulation activities to frame the scientific questions that will be the focus of the assessment, which is conducted employing the principles of systematic review. A draft assessment plan for chloroform was posted publicly and also presented at a September 27−28, 2017 Science Advisory Board Chemical Assessment Advisory Committee (SAB CAAC) public meeting to seek input from the scientific community and interested parties on the problem formulation components of the assessment plan. The draft assessment plan contains a summary of the IRIS Program’s scoping and problem formulation conclusions; the objectives and specific aims of the assessment; draft Populations, Exposures, Comparators, and Outcomes (PECO) criteria; and identification of key areas of scientific complexity. The protocol then incorporates the elements of the assessment plan, but also presents more detailed methods for conducting the systematic review and dose-response analysis, including any adjustments made to the specific aims and PECO in response to public input into the assessment plan. While the IRIS Assessment Plan describes what the assessment plans to cover, chemical-specific protocols describe how the assessment will be conducted (see Figure 1). The IRIS Program posts assessment protocols on its website and considers public input while preparing the draft assessment. Major updates to the protocol (e.g., fundamental alterations to the PECO or addition of literature search results) will trigger release of a revised protocol document and an additional public comment period