Hazardous Waste Program

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Risk-Based Corrective Action

Departmental MRBCA | MRBCA for Petroleum Storage Tanks

In 1995, the General Assembly passed House Bill 251, which directed the Clean Water Commission to use risk-based corrective standards to clean up underground storage tank sites. In 1999, the General Assembly passed Senate Bill 334, which directed the Clean Water Commission to develop a process to determine if risk-based remediation of groundwater was appropriate for any particular site. Although separate actions, both directives aimed to facilitate risk-based remediation decisions within the department. Later, Senate Bill 901 (signed in 2004) gave regulatory authority for tanks, including authority for risk-based remediation rules, from the Clean Water Commission to the Hazardous Waste Management Commission.

What is the MRBCA process?
A risk-based corrective action, or RBCA, process provides a framework for remediation decisions at contaminated sites. It protects human health and the environment while allowing constructive current and future site use.

Using a risk-based process, site remediation is based on site-specific human health and environmental risk from exposure to contamination. Safe levels of contaminants of concern are based on land use (residential or non-residential) an the analysis of exposure pathways such as direct exposure to surface soil, groundwater use, vapor intrusion into buildings, and others.

In some cases contamination may be left in place with appropriate controls, whether engineering or institutional controls or both, to ensure long-term protection.

A risk-based framework can streamline the process of site cleanup and closure, streamline decision-making, clearly define endpoints and focus finite resources (both private and public) on sites with the highest current or potential risks. By adopting a risk-based process that applies to most contaminated sites, the department can provide greater consistency in its decision-making.

The department has two risk-based corrective action processes:

Departmental Missouri Risk-Based Corrective Action
This department-wide guidance provides a framework for environmental professionals, both in the public and private sectors, for the process, methodologies, and key elements of Risk-Based Corrective Action.

In 2009, the department, with the assistance of certain stakeholders, developed a risk-based corrective action rule to codify the process and its key elements and methodologies. The rulemaking process involved both the Clean Water Commission and the Hazardous Waste Management Commission. The rule, 10 CSR 25-18.010 Risk-Based Corrective Action Process, was adopted in June 2009 and became effective on October 31, 2009.

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Missouri Risk-Based Corrective Action Process for Petroleum Storage Tanks
The department has published a separate technical guidance for tanks. The guidance is available online or by contacting the department at 800-361-4827.

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