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Introduction to Risk-Based Corrective Action (RBCA)

What is Risk-based corrective action (RBCA)?

Risk-based corrective action (RBCA) is a generic term for corrective action strategies that categorize sites according to risk and move all sites toward completion using appropriate levels of action and oversight. The ASTM standard is a good example of a framework for implementing a RBCA strategy. With this process, regulators can make sound, quick, consistent management decisions for a variety of sites using a three-tiered approach to data collection and site review contained in ASTM's E1739 standard guide for "Risk-Based Corrective Action applied at Petroleum Release Sites."

Tier 1 consists of a qualitative risk-assessment based on general site assessment information.

This data would need to identify obvious environmental impacts (if any), potentially affected sensitive receptors (schools, homes, water bodies, etc.), and significant exposure pathways (drinking water wells, recreational use of streams, vapor transport, etc.).

When gathered for a number of sites, this information is typically sufficient to help categorize sites and determine acceptable time frames for corrective action (immediacy of response), if necessary.

Tier 2 sees more site-specific data utilized to determine the appropriate risk-based actions.

Here, the reasonable maximum site-specific impact is evaluated through the use of site-specific characterization and monitoring data, conservative projections of expected levels of contaminates after treatment and potential plume migration, and reasonable maximum exposure scenarios.

This information is used to set conservative corrective action objectives that are protective of human health and the environment.

Tier 3 focuses completely on the site-specific conditions.

More sophisticated mathematical descriptions of fate and transport phenomena are used and descriptions of the range of possible exposures/risks are generated. At this level of complexity, site specific risk assessment models may be developed.

Due to the costs involved, this analysis is suited to only large sites.

Contact us

Steve Beukema, at BeukemaS@Michigan.gov or 269-547-0125.