Missouri
Missouri Risk-Based Corrective Action (MRBCA)
The Missouri Risk-Based Corrective Action (MRBCA) process is the framework the Missouri Department of Natural Resources uses for cleanup decisions at contaminated sites. The department works with sites, mainly those enrolled in its Brownfields/ Voluntary Cleanup Program or its Underground Storage Tank Program, to investigate and clean up releases of chemicals to soil, groundwater, surface water and air. Where removing every trace of contamination is not possible or practical, it uses the risk-based process.
In a Phase I ESA
ASTM E1527-21 does not name risk-based cleanup guidance among its standard record sources. It matters because it explains what a closed Missouri cleanup file means. A site closed under MRBCA was cleaned to a level that rests on its current and planned use and on the exposure pathways, and contamination may remain.
- Cleanup levels follow land use. The department says acceptable levels rest on current and planned future use, residential or non-residential, and on the exposure pathways from the source to people, animals or the environment. It gives the example that a warehouse redeveloped as residential apartments would need different cleanup levels and controls than continued industrial or commercial use. Ask which use a closed file assumed, and compare it with the use now planned.
- Contamination may be left in place. The department says contamination may stay if it is determined to be safe and institutional or engineering controls ensure long-term protection. See Risk-Based Cleanup Tools, Controls and Resources.
- Vapor intrusion is among the pathways. The department names volatilizing chemicals from soil or groundwater entering buildings as an indirect pathway.
Two sets of guidance
The department has two separate technical guidance documents.
- Tanks MRBCA guidance applies to petroleum releases at petroleum storage tank sites. The department posts the 2004 version, as modified in March 2005, and the October 2013 version. Its sections 6.9 and 11 allow activity and use limitations in a corrective action plan.
- Departmental MRBCA guidance applies mainly to voluntary cleanups overseen by the Brownfields/ Voluntary Cleanup Program. It has three evaluation tiers, with rising site-specific detail, complexity and cost, and the department says most sites are cleaned up under Tier 1. Its Risk-Based Target Levels are described as conservative default cleanup levels used to guide investigation, decide whether further action is needed and decide when enough cleanup has occurred.
In 2009 the department developed a rule to codify the departmental process. It is 10 CSR 25-18.018 and took effect October 31, 2009. The department says the rule and the current departmental guidance are both used. The departmental guidance posted includes updates made in June 2006 and June 2008.
Where to look a site up
MRBCA is a method and not a list. The sites it governs are in the Brownfields/ Voluntary Cleanup Program (BVCP) records, the Regulated Storage Tank Cleanup and Closure records, and the E-Start map. The target level tables and guidance sections are documents on the department's website, which this handbook has not opened.
Getting the file
The pages read do not give an MRBCA-specific records route. The department's general route is the Sunshine Law request.
Sources
Missouri Department of Natural Resources pages, read October 8, 2026, no modified date shown: