Molds are fungi which grow in moist environments, and therefore can often develop where flooding has occurred. While most molds are harmless, some can cause infections, allergy symptoms, or produce toxins. Mold remediation often is necessary before cleanup and renovation of flooded areas to avoid an unhealthy environment for workers.
Most important is to create a mold cleanup plan before beginning. The first step in eliminating mold is to control the moisture where it thrives. The types of materials in the area must be assessed to determine the strategy for remediation and protecting workers. The size of the area must also be considered. Materials that cannot be dried or fully cleaned must be removed using methods that will minimize the workers’ exposure. Often it may be more cost-effective to replace building materials than to attempt to dry and clean mold-contaminated materials. If the materials seem salvageable, fans, blowers, and/or humidifiers can be used to dry them, but if there is too much humidity in the air, these methods may not be completely effective.
If the area of mold remediation is less than 30 square feet, the work area should be unoccupied, but people in adjacent spaces do not necessarily need to be removed. The exceptions are infants, persons recovering from surgery, immune-suppressed people, and people with asthma, hypersensitivity pneumonitis, and severe allergies. It is not necessary to contain a small work area, but surfaces that might be contaminated should be covered with secured plastic sheets to contain dust and debris and prevent the spread of contamination. For larger areas of 30 to 100 square feet, areas directly adjacent should be unoccupied and ventilation ducts and grills in the work area and adjacent areas should be sealed. The surfaces in the work area should be covered with secured plastic sheets to contain spores, dust, and debris that may spread contamination.
If there is a visibly heavy concentration of mold, or the remediation procedures are expected to generate a lot of dust, such as when plaster walls must be demolished or abrasive cleaning of contaminated surfaces is necessary, additional steps must be added to the mold remediation plan. It may be necessary to consult with industrial hygienists or other environmental health and safety professionals experienced with mold remediation for this level of remediation. The work area must be isolated and may require the use of airlocks or a decontamination room. Exhaust fans with high-efficiency particulate air (HEPA) filtration may be needed for drying the area.
Assessing the type of materials to be cleaned will help determine the methods needed. Non-porous materials such as metal, glass, and hard plastics can be dried, fully cleaned, and reused. Detergent can be used to clear hard and non-porous surfaces. A disinfectant made by mixing ½ cup of liquid household bleach into one gallon of water can be used to rinse the surfaces. Be careful to AVOID mixing bleach with any cleaning products containing ammonia. Semi-porous materials such as wood and concrete can be cleaned if they are structurally sound. Porous materials such as drywall, carpets, insulation, and ceiling tile are difficult to fully clean as mold can penetrate into them. If the porous material has been wet for more than 48 hours, it is best to remove and replace it.
There are three methods that can be used to protect workers during mold remediation.
Engineering controls include:
• Providing natural or local exhaust ventilation during all cleanup steps
• Re-wetting materials with a mist of water to help prevent the spread of spores, dust, and debris
• Wrapping and sealing the items that will be discarded in plastic bags or sheets to reduce the spread of spores
Personal Protective Equipment (PPE) includes:
• Non-vented goggles
• Long gloves of a material that will protect workers from any chemicals that may be used for surface cleaning
• Protective clothing such as disposable coveralls to prevent contamination and skin contact with mold and chemicals. For larger areas over 100 square feet, protective clothing should cover the entire body including head and feet.
Work Practices that protect workers include:
• No eating, drinking or smoking in work areas
• Avoid breathing dusts
• Vacuum the area with a HEPA vacuum after the it has been cleaned and is completely dry. HEPA vacuums will also help remove dust that may have settled on surfaces outside the work area
• A decontamination area should be set up. The area should be kept clean using a damp cloth or mop and a detergent solution
• After working, wash thoroughly, including hair, scalp, and nails
Following a plan using these steps will help keep workers safe during mold remediation. For additional information on this topic, visit www.osha.gov.