RBCA is a consistent decision-making process for the assessment and response to a chemical release, based on the protection of human health and environment. RBCA uses a three-tier approach as defined in ASTM PS-104 "Standard Provisional Guide for Risk-Based Corrective Action" (ASTM, 1998). TEC uses computer modeling (RBCA Tool Kit, BIOSCREEN, BIOCHLOR, and Johnson & Ettinger Model) in its performance of multi-tiered RBCA.