Research Highlights

Building Decontamination Alternatives Report

Building decontamination information available for regulators and environmental professionals

EPA has published a building decontamination alternatives report, which provides information on how to effectively decontaminate buildings that are contaminated with chemical or biological (CB) warfare agents or toxic industrial compounds. The report includes the review for three categories of technologies:

• Liquid
• Foam and gel
• Gas and vapor-phase.

The following information is provided for each technology reviewed:

• A description
• An assessment of the technical maturity
• An evaluation of existing data (wherever possible, information on material compatibilities, hardware performance, and generation of by-products is provided)
• Current uses in addition to building decontamination
• User concerns (e.g., health and safety issues)
• Advantages and disadvantages
• Future research areas.

The report does not present an exhaustive review of all potential technologies. It focuses on technologies available prior to March 2005 that show the most promise with respect to commercial use in related applications such as medical sterilization or on actual/potential use in building decontamination.

The following is a summary of the technologies discussed in the report:

Liquid technologies involve applying decontamination solutions directly on a surface contaminated with a CB agent. The solution may later be removed by wiping or wet vacuuming. Liquid technologies reviewed in the report include hypochlorite (bleach or sodium hypochlorite, as well as other hypochlorite-based technologies), aqueous chlorine dioxide, liquid hydrogen peroxide, and a proprietary product (TechXtract®).

Foam and gel technologies are designed to neutralize or inactivate CB warfare agents through application to vertical and horizontal surfaces such as walls, floors, and ceilings. Sufficient contact time with the surface is also a factor in the neutralization/inactivation process. Foam and gel technologies reviewed in the report include Sandia Foam, Decon Green®, CASCAD, and L-Gel.

Gas and vapor-phase (fumigant) technologies require complete sealing of the area to be decontaminated to prevent gas or vapor escape. This may mean tenting an entire structure or sealing openings in a target zone or throughout an entire building. The gas or vapor is injected into the sealed area and allowed to remain for the time required to ensure treatment. The fumigant is removed during or after decontamination with a gas adsorption system to prevent release of the hazardous decontaminant gas to the atmosphere. Gas and vapor-phase technologies reviewed in the report include chlorine dioxide gas, hydrogen peroxide vapor, paraformaldehyde, and methyl bromide.

Summary and Conclusions

No single technology can be applied in all situations. Some of the technologies reviewed have incompatibilities with certain materials. The pH of the liquid, foam, or gel solution used can have detrimental effects on materials, too. Liquids may be more appropriate for decontamination of hard surfaces, but could also be used on porous surfaces depending on whether the decontaminated material is to be disposed of or retained. Foams and gels appear to be effective on vertical or porous surfaces; however, further study is required. Using foam and gels also might create post‑decontamination cleanup issues. Gases and vapors can be effective against biological contamination under controlled conditions (e.g., sterilization chambers) and in some field applications. In addition, gases and vapors were used successfully to decontaminate many of the buildings contaminated with Bacillus anthracis spores in 2001. However, fumigant technologies need to be further evaluated for large-building scenarios. Little information is available on the ability of gases and vapors to decontaminate chemical warfare agents.

Many of the decontamination technologies look promising. However, at the time of the report’s release, some technologies were either not close enough to commercialization (enzyme-based technologies, photochemical systems), presented human health hazards (ethylene oxide), or were untested in building applications (ozone, plasma, directed energy) to warrant their inclusion. The research used to prepare this report has provided information that can be useful when prioritizing decontamination technologies for further evaluation.

Contact: Joseph Wood

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