In a discussion that included inputs from eleven delegates representing six states, it was found that there is variation among our state extension resources on the amount of bleach to be used when removing flood-induced mold, but all were essentially consistent with EPA guidelines. The EDEN Mold page is extensive, and the point of contact for that page - Ken Hellavang (ND) – wound up our discussion with a summary, from which the following salient points are derived:
- The EPA does not list using chlorine bleach or any biocide for mold removal. Part of the reason for that recommendation is that mold must be physically removed to eliminate the health hazard of mold. The other is that there is a hazard associated with using any biocide including bleach.
- However, flood cleanup includes removal of bacteria and other biological materials in addition to mold. Therefore, for flood cleanup, the recommendation continues to be to use chlorine bleach or other approved biocide on non-porous and semi-porous materials AFTER the material has been thoroughly cleaned. Chlorine is inactivated by organic material so unless the surface is clean, the bleach will not properly disinfect/sanitize the surface.
- Chlorine bleach is a registered product that carries a label identifying how to use the product and the application for which it has been approved. Clorox bleach for example indicates that the concentration for their product is ¾ cup of bleach per gallon of water, that enough of the solution needs to be applied to keep the surface wet for at least five minutes, the surface should be rinsed and dried. (The label is the law for a biocide.)
In the discussion a relatively new HUD publication was brought to our attention by Howard Van Dijk (SC-Retired) - Rehabbing Flooded Houses: A Guide for Builders and Contractors. Rehabbing Flooded Houses is a guidebook for professional builders and contractors rehabbing flooded single-family houses. Homes flood for a variety of reasons (overflowing rivers, high coastal waves, hurricanes, etc.) but the methods for determining how badly the building has been damaged and how to repair it are relatively similar no matter where you are working. The emphasis in this guidebook is on safe practices and the most important activities in the rehab process. This guidebook is bilingual in English and Spanish.
The discussed veered into the related issue of moisture content and other treatments of wall studs, and how to minimize future mold and rot problems.
Several members of the EDEN/Flood CoP were together for an eXtension meeting this week and will be developing new materials based on these discussions.
Discussants not named above included Bev Maltsberger, Frank Wideman, Sherry Nelson, BJ Eavy and Bob Schultheise (all from Missouri), Shirley Niemeyer (NE), Becky Koch (ND), and Pat Skinner (LA), with Virginia Morgan (VA), Linda Fischer (IA) and Bill Hoffman (USDA-NIFA) monitoring.