Mold Remediation Basics
People commonly ask how to remove mold or how to kill mold. Mold remediation is conducted using a variety of approaches depending on the size and complexity of the contamination as well as the technology available to the contractor. The Environmental Protection Agency’s Mold Remediation in Schools and Commercial Buildings guidelines are commonly utilized. The methods and principles outlined are a good guide for professional remediation of commercial and residential buildings.
In 2008 New York City Department of Health and Mental Hygiene (DOHMH) issued revised mold remediation guidelines that are also widely followed by mold remediation contractors. In 1993, the DOHMH first issued recommendations on addressing mold growth indoors based on a growing need for guidance on how to deal with mold contamination. The 2008 document should be used only as guidance. It cannot be used in lieu of a site-specific mold assessment and mold remediation plan and is not intended to be utilized in critical care facilities such as intensive care units, transplant units, or surgical suites. Currently there are no United States Federal, New York State, or New York City regulations for the assessment or remediation of mold growth.
The guidelines describe four levels of contamination based on the size of the infected area and a fifth for contaminated HVAC systems.
- Level 1 (10 sq. ft. or less): remediation usually involves cleaning and salvaging non-porous materials with a detergent solution and removing non-salvageable contaminated porous materials.
- Level 2 (10–30 sq. ft.): follow steps as Level 1, plus covering working areas in plastic and tape before remediation and using a High-Efficiency Particulate Air (HEPA) filter before restoration begins.
- Levels 3 (30–100 sq. ft.) and 4 (over 100 sq. ft.): involve specialized techniques for removing hazardous materials. Negative pressure sealed containment is required.
- Level 5: used for contaminated HVAC systems.
Mold remediation contractors utilize HEPA filters, cleaners, wet vacuums, HEPA vacuums, biocides (disinfectants), and Personal Protective Equipment (PPE). Safety precautions are extremely important in mold remediation to prevent both exposure to and spread of hazards. Gloves, fitted goggles, disposable protective clothing, and a professionally fitted respirator typically are needed to protect workers performing remediation.
Techniques used by some professionals to remove mold include, but are not limited to, cutting and removing contaminated sheetrock and other building materials, cutting and scraping, steam cleaning, and washing with a detergent and bleach solution. A study of biocide solutions showed the detergent and bleach solution to be the most effective.