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Testing antimicrobial cleaner efficacy on gypsum wallboard contaminated with Stachybotrys chartarum
Marc Y Menetrez1, Karin K Foarde, Tricia D Webber
1US Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, Air Pollution Prevention and Control Division, Research Triangle Park, NC 27711, USA. menetrez.marc@epa.gov
Goal, Scope And Background:
Reducing occupant exposure to indoor mold is the goal of this research, through the efficacy testing of antimicrobial cleaners. Often mold contaminated building materials are not properly removed, but instead surface cleaners are applied in an attempt to alleviate the problem. The efficacy of antimicrobial cleaners to remove, eliminate or control mold growth on surfaces can easily be tested on non-porous surfaces. However, the testing of antimicrobial cleaner efficacy on porous surfaces, such as those found in the indoor environment such as gypsum board can be more complicated and prone to incorrect conclusions regarding residual organisms. The mold Stachybotrys chartarum has been found to be associated with idiopathic pulmonary hemorrhage in infants and has been studied for toxin production and its occurrence in water damaged buildings. Growth of S. chartarum on building materials such as gypsum wallboard has been frequently documented.
Methods:
Research to control S. chartarum growth using 13 separate antimicrobial cleaners on contaminated gypsum wallboard has been performed in laboratory testing. Popular brands of cleaning products were tested by following directions printed on the product packaging.
Results:
A variety of gypsum wallboard surfaces were used to test these cleaning products at high relative humidity. The results indicate differences in antimicrobial efficacy for the six month period of testing.
Discussion:
Results for the six types of GWB surfaces varied extensively. However, three cleaning products exhibited significantly better results than others. Lysol All-Purpose Cleaner-Orange Breeze (full strength) demonstrated results which ranked among the best in five of the six surfaces tested. Both Borax and Orange Glo Multipurpose Degreaser demonstrated results which ranked among the best in four of the six surfaces tested.
Conclusions:
The best antimicrobial cleaner to choose is often dependent on the type of surface to be cleaned of S. chartarum contamination. For Plain GWB, no paint, the best cleaners were Borax, Lysol All-Purpose Cleaner-Orange Breeze (full strength), Orange Glo Multipurpose Degreaser, and Fantastik Orange Action.
Recommendations And Perspectives:
These results are not meant to endorse the incomplete removal of mold contaminated building materials. However, it is recognized that complete removal may not always be possible and solutions to control mold regrowth may contribute to reduced occupant exposure. Current recommendations of removal and replacement of porous building materials should be followed. It is not the intension of this discussion to endorse any product. Reporting on the performance of these products under the stated conditions was and remains the only purpose.
Insights
This study tested antimicrobial cleaners on gypsum wallboard contaminated with Stachybotrys chartarum mold. Lysol All-Purpose Cleaner-Orange Breeze, Borax, and Orange Glo showed the best mold control on various surfaces.
Area of Science:
- Environmental Science
- Microbiology
- Building Science
Background:
- Indoor mold, particularly Stachybotrys chartarum, poses health risks, including idiopathic pulmonary hemorrhage in infants.
- Incomplete removal of mold-contaminated building materials is common, leading to reliance on surface cleaners.
- Testing antimicrobial cleaner efficacy on porous materials like gypsum wallboard is complex due to potential residual organisms.
Purpose of the Study:
- To evaluate the efficacy of 13 antimicrobial cleaners in controlling Stachybotrys chartarum growth on gypsum wallboard.
- To identify effective cleaning solutions for porous building materials to reduce indoor mold exposure.
- To compare cleaner performance across different gypsum wallboard surface types.
Main Methods:
- Laboratory testing of 13 antimicrobial cleaners on Stachybotrys chartarum-contaminated gypsum wallboard.
- Application of cleaners according to manufacturer's instructions.
- Assessment of mold control efficacy over a six-month period under high relative humidity.
Main Results:
- Significant differences in antimicrobial efficacy were observed among the tested cleaners.
- Lysol All-Purpose Cleaner-Orange Breeze (full strength) ranked among the best on five of six tested surfaces.
- Borax and Orange Glo Multipurpose Degreaser performed well on four of six surfaces.
Conclusions:
- Antimicrobial cleaner effectiveness varies by gypsum wallboard surface type.
- For plain, unpainted gypsum wallboard, Borax, Lysol All-Purpose Cleaner-Orange Breeze, Orange Glo, and Fantastik Orange Action were most effective.
- While material removal is recommended, effective cleaners can help control mold regrowth and reduce occupant exposure.
