An owner or operator of a regulated petroleum storage facility is responsible for assessing and remediating a petroleum release upon discovery. The Colorado Division of Oil and Public Safety (OPS) utilizes a formal method of risk evaluation based on the American Society of Testing and Materials Standard E 1739-95, Standard Guide for Risk-Based Corrective Action (RBCA) Applied at Petroleum Release Sites. This approach of risk evaluation allows for multiple closure criteria, or tiers, to be applied to a petroleum release. The purpose of this guidance document is to describe the tiered closure approach utilized by OPS. Common elements associated with all petroleum release closure evaluations will be presented, along with the criteria and applicability associated with each tier of risk evaluation.
