ASSE Offers Cleanup Tips for Flood-Related Mold

Besides infection and allergic reactions, excessive mold growth indoors can result in offensive, musty odors from the gases released by certain molds as they grow and die.

Mold grows easily in flood-related conditions, which include standing water, humid air, and wet surfaces, according to the American Society of Safety Engineers (ASSE). To address this, ASSE offers the following tips for people to consider when looking at how to clean up mold and minimize its adverse effects.

“For businesses, addressing mold and moisture after a flood disaster should be the first step to reduce the risk to others who may need to work in an affected building,” said ASSE Assistant Director of School Plant Services and Environmental & Energy Management James H. Morris.

The U.S. Environmental Protection Agency (EPA) recommends that “surfaces wet longer than 48 hours with clean water should be considered as potentially contaminated, and any surfaces in contact with dirty water should be considered contaminated.” ASSE recommends that people consult their state and local experts for more guidance regarding state and local laws and regulations addressing mold.

In addition, to lessen the chances of a mold colony growing in a store/business, the U.S. Centers for Disease Control (CDC) recommends:

  • the humidity level be kept below 50 percent;
  • an air conditioner or dehumidifier be used during humid months (depending on the climate);
  • adequate ventilation, including exhaust fans in the kitchen and bathrooms, be used;
  • to add mold inhibitors to paints before applying them;
  • bathrooms be cleaned with mold-killing products; and
  • not to put carpeting in bathrooms, basements, or other areas where moisture or water could be a concern.

Mold is a group of microscopic fungi, which also includes mildew and other organisms that rot materials on which they grow. Molds can often be invisible to the eye. A blotch of black, gray, white, red, orange, yellow, blue, or violet fuzzy or slimy growth is usually the result of widespread mold growth. Besides infection and allergic reactions, excessive mold growth indoors can result in offensive, musty odors from the gases released by certain molds as they grow and die.

“During all mold cleanup operations, individuals should wear proper personal protection equipment, which includes gloves, goggles, and a respirator,” Morris said. “However, the type of respirator varies on the size of the area affected by mold and on the work area. Workers who wear respirators should be medically cleared to use such protection, and trained in the use of their equipment.”

ASSE offers the following tips for cleaning a facility/building area affected by mold:

  • Avoid direct contact with affected mold areas as much as possible.
  • If it can be thrown away, throw it away. Replacements may be less expensive in the long term (and short term) than attempting to decontaminate some surfaces.
  • If it cannot be disposed of, decontaminate and then dry as thoroughly as possible. Moisture removal is a key factor to preventing future growth.
  • Wallboard can often be cut to the point of contamination and replaced with new sections.
  • Clean all tools after use, or dispose if possible, and also clean tools after each shift.
  • When in doubt about the structural integrity of a facility, obtain an evaluation by a licensed and qualified builder or structural engineer before entering. Medical clearance may also be necessary based upon the severity of mold in the area.
  • Individuals involved in mold remediation should be aware that attempts to mix chemicals to clean surfaces can cause further damage, such as the toxic gases that can be released when ammonia and bleach are mixed. Workers need to exercise caution, so as not to create additional hazards.
  • The power supply (circuit breakers) should be turned off in the specific damaged areas/high levels of moisture to avoid electrical shock hazards.

Mold safety information can be found at

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  • OHS Magazine Digital Edition - April 2021

    April 2021


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