14.1. Decontamination/Cleanup Planning:
Once site controls are in place, develop a site-specific decontamination/cleanup plan. Environmental decontamination may
require a “tiered approach” using a variety of techniques and products. Call EPA/HQ-EOC at 202-564-3850 for more
information.
General Considerations: A cost vs. benefit evaluation should be undertaken for each decontamination strategy and
approach that considers public safety, total cost, impact on the area, wastes generated, time the area or item will be
inaccessible and/or out of service, as well as any socio-economic, public health, and/or security impacts that may result.
Large volumes of decontamination wastes may be generated that will need to be collected, treated, and disposed of
properly. Waste handling and disposal must be addressed as early in the decontamination and cleanup process as
possible (see WASTE MANAGEMENT section below).
Disposal Option: The urgency to restore an area or item as quickly as possible may result in the outright and timely
removal and disposal of contaminated materials. Certain materials may be impacted by the decontamination products,
and/or may be cheaper to discard and replace than to decontaminate and restore.
Monitored Natural Attenuation: Sarin degrades via natural processes. Environmental monitoring must be maintained
during decontamination and recovery phases. Monitored natural attenuation may require institutional controls (e.g.,
access restriction and contaminant containment measures). The time to achieve clearance must be considered in the
overall cost/benefit evaluation. This option is more passive than other options but is non-destructive to materials.
Fix-in-Place Option: The contaminated area may be resistant to decontamination products or may be unable or
impractical to be treated. Physical barriers can be used to immobilize the contamination and prevent it from coming into
contact with the environment or the public. This can be a temporary or permanent solution.
14.2. Decontamination Strategy:
A decontamination strategy can be developed by designating contaminated areas into five broad categories: 1) surfaces or
hot spots, 2) large volumetric spaces, 3) sensitive equipment or items, 4) aqueous solutions, and 5) water systems. Areas in
each category may be treated using one or more unique decontamination processes in a tiered approach to the overall site-
specific decontamination strategy.
Cautions:
• Decontamination products may have unique safety/PPE requirements due to their own toxicity or that of breakdown
products during use (e.g., use of bleach results in release of chlorine vapors). Strong oxidizers, such as hypochlorite,
may react violently with organics.
• Dirt, grime, and other coatings (organic load) can reduce the efficacy of decontamination; pre-cleaning surfaces with
soap and water may be needed before the application of decontamination formulations but resulting pre-cleaning
rinsates require containment to avoid agent spread.
For additional information, contact the EPA/HQ-EOC at 202-564-3850.
Surfaces/Hot Spots: This category is for areas smaller in size but with higher levels of agent contamination. They may
require more rigorous decontamination products and methods. Excess Sarin liquid should be absorbed using, e.g.,
vermiculite or dry sand, and transferred into a sealed container and disposed according to WASTE MANAGEMENT
section below. Decontamination of remaining Sarin occurs mainly through hydrolysis, which occurs faster at high pHs,
although other mechanisms may cause and/or catalyze (speed up) Sarin destruction. Hydrolysis of Sarin produces
fluoride ions, which may form HF at low pH. Application of the following decontamination solutions and formulations
may be efficacious by following applicable manufacturers’ directions.
1) Hypochlorite-containing solutions: Hypochlorite can be corrosive to certain surfaces and materials and should be
rinsed thoroughly afterwards. Household bleach solutions (≥5% sodium hypochlorite) are effective for Sarin with
efficacy achieved with contact time of 15-60 minutes depending on surface material. Calcium hypochlorite, present
in commercial products, such as HTH (10% hypochlorite solution), is better for surfaces with high concentrations of
liquids in localized areas. Note that lowering the pH of hypochlorite solutions is not required and may be
counterproductive.
2) Hydroxide (e.g., sodium, potassium – 10% solution) reacts rapidly with Sarin, but solutions are very damaging to
many surfaces and should be rinsed thoroughly after use.
3) Other high pH solutions, such as sodium carbonate (10% solution), have been shown to decontaminate surfaces but
slower than decontamination with sodium or potassium hydroxide, which have higher pH.
4) Proprietary decontamination technologies such as EasyDecon DF-200®, Decon7 (D7), Dahlgren Decon®,
CASCAD®, Decon Green®, or L-Gel® have been shown to be effective against Sarin on the order of minutes to
hours, but not all have been thoroughly tested. Availability, cost, and the need for specialized equipment to apply the
decontaminant may limit their use early in the response.
Large Volumetric Spaces: This category is for areas larger in size but with lower levels of agent contamination. These
areas may require less aggressive but more broadly applied decontamination products and methods.
1) Monitored Natural Attenuation is more passive than other decontamination options and is non-destructive to
materials. This option may be preferable given the scope and severity of contamination, especially given Sarin’s
relative high volatility.