Moulds are microorganisms which are present throughout indoor and outdoor environments. Moulds produce thousands of tiny particles called spores, which are released into the air when disturbed by air movement or handling.  Particles of the moulds themselves can also become airborne in the same way.  In the indoor residential setting, individuals can be affected when the airborne particles are inhaled or come into contact with the skin.  The effect on health can range from none to allergic reactions and illness, depending on several factors, including: the type of mould; the health condition of the individual; the amount, duration, and frequency of exposure to the mould particles.  Pregnant women, infants, allergic individuals, the elderly and those with health problems such as a weakened immune system or respiratory disease are most at risk when exposed to mould.  Although there are very few documented cases of health problems resulting from indoor exposure to moulds, the Peterborough County-City Health Unit recognizes that reactions to mould exposure vary widely with the individual; there is not known “safe” or “unsafe” level of exposure for people in general.

Some moulds produce toxins which can cause adverse health effects in most members of the population.  However, even moulds commonly found in residential settings can cause flu-like symptoms after a heavy exposure during activities such as renovations or cleaning of very widespread mould growth.  Common allergic reactions are runny nose, eye irritation, cough, congestion, and aggravation of asthma.  Since the cause of reactions to moulds can be so varied, it is generally not necessary, or time- and cost-effective,  to identify the species of mould growing in a residence.

Mould Remediation

In buildings with water damage or ongoing moisture problems, moulds may reproduce to higher than normal levels, and potentially cause adverse health effects.  In such situations, it is critical that the source of the moisture be found and eliminated before the cleaning and remediation of any mould-affected area can be effective.

Mould contamination is often visible, and a large mould infestation can usually be smelled.  In residential areas which have been flooded or subjected to excessive water, mould growth may occur or be present behind wallboard, ceiling tiles, and insulation, and under carpets.   These should be removed unless invasive examination shows that the area is dry and there is no mould growth.  Carpet without attached underpad may be reused if commercially cleaned and immediately thoroughly dried.
Routine mould removal: In most cases, small areas of mould, such as those growing on window frames, or in bathrooms between tiles and around bathtubs, can be safely removed by thoroughly washing with detergent and water,  rinsing with clear water, and drying very quickly.  This work can be done by the resident, unless they are allergic or otherwise sensitive to moulds. 

Small areas (up to 3 patches, each no larger than 1 square metre): Use safety glasses or goggles, a disposable dust mask (N95 rated), and household rubber gloves.  Clean washable surfaces with a detergent and water solution, rinse with clear water, and dry very quickly.   Individuals allergic or sensitive to moulds should not attempt this work. 

Large Areas (3 - 10 square metres):  To clean large areas, up to 10 square metres:
• the work area should be vacated;
• use safety glasses or goggles, a disposable dust mask (N95 rated), and household rubber gloves;
• isolate the area to be cleaned with plastic sheeting, tapes to walls and ceiling;
• vacuum surfaces with a vacuum cleaner which is equipped with a HEPA (high efficiency particulate air) filter, or is exhausted to the outside; scrub or brush the mouldy area with a detergent and water solution, rinse with clear water, and dry very quickly;
• if surfaces still appear to be mouldy, clean with a TSP (trisodium phosphate) and water solution, rinse twice with clear water, and dry very quickly; and
• HEPA vacuum the surfaces in surrounding areas.
Individuals allergic or sensitive to moulds should not attempt this work.

Mould remediation which involves renovation or removal of building materials can cause mould particles to become airborne, and may result in allergic or respiratory symptoms.  This work should be completed in accordance with accepted industry standards for worker protection and safety.  Infants (under 12 months old), persons recovering from recent surgery, or people with immune suppression, asthma, hypersensitivity pneumonitis, severe allergies, sinusitis, or other chronic inflammatory lung diseases should leave adjacent areas until the work has been completed.  Any other persons exhibiting symptoms of adverse reactions to mould should also be advised to relocate. 

Extensive Contamination (areas greater than 10 square metres): These areas should be remediated by, or under the guidance of personnel trained in the handling of hazardous materials.

Precautions to be taken for repeated or long-term remediation exposures:
Professionals or others who work repeatedly in mould abatement should follow the more stringent standards found in “Guidelines on Assessment and Remediation of Fungi in Indoor Environments”, developed by the New York City Department of Health and Mental Hygiene.  These are as follows:

Level I - Small Isolated Areas (10 sq. ft or less) - e.g., ceiling tiles, small areas on walls
Remediation can be conducted by regular building maintenance staff. Such persons should receive training on proper clean up methods, personal protection, and potential health hazards. This training can be performed as part of a program to comply with the requirements of the OSHA Hazard Communication Standard (29 CFR 1910.1200). Respiratory protection (e.g., N95 disposable respirator), in accordance with the OSHA respiratory protection standard (29 CFR 1910.134), is recommended. Gloves and eye protection should be worn. The work area should be unoccupied. Vacating people from spaces adjacent to the work area is not necessary but is recommended in the presence of infants (less than 12 months old), persons recovering from recent surgery, immune suppressed people, or people with chronic inflammatory lung diseases (e.g., asthma, hypersensitivity pneumonitis, and severe allergies). Containment of the work area is not necessary.  Dust suppression methods, such as misting (not soaking) surfaces prior to remediation, are recommended.  Contaminated materials that cannot be cleaned should be removed from the building in a sealed plastic bag. There are no special requirements for the disposal of mouldy materials.  The work area and areas used by remedial workers for egress should be cleaned with a damp cloth and/or mop and a detergent solution.  All areas should be left dry and visibly free from contamination and debris.

Level II -  Mid-Sized Isolated Areas (10 - 30 sq. ft.) - e.g., individual wallboard panels.
Remediation can be conducted by regular building maintenance staff. Such persons should receive training on proper clean up methods, personal protection, and potential health hazards. This training can be performed as part of a program to comply with the requirements of the OSHA Hazard Communication Standard (29 CFR 1910.1200).  Respiratory protection (e.g., N95 disposable respirator), in accordance with the OSHA respiratory protection standard (29 CFR 1910.134), is recommended. Gloves and eye protection should be worn.  The work area should be unoccupied. Vacating people from spaces adjacent to  the work area is not necessary but is recommended in the presence of infants (less than 12 months old), persons having undergone recent surgery, immune suppressed people, or people with chronic inflammatory lung diseases (e.g., asthma, hypersensitivity pneumonitis, and severe allergies).  The work area should be covered with a plastic sheet(s) and sealed with tape before remediation, to contain dust/debris. Dust suppression methods, such as misting (not soaking) surfaces prior to remediation, are recommended.    Contaminated materials that cannot be cleaned should be removed from the building in sealed plastic bags. There are no special requirements for the disposal of mouldy materials.  The work area and areas used by remedial workers for egress should be HEPA vacuumed (a vacuum equipped with a High-Efficiency Particulate Air filter) and cleaned with a damp cloth and/or mop and a detergent solution.  All areas should be left dry and visibly free from contamination and debris.

Level III - Large Isolated Areas (30 - 100 square feet) - e.g., several wallboard panels.
A health and safety professional with experience performing microbial investigations should be consulted prior to remediation activities to provide oversight for the project.  The following procedures at a minimum are recommended:  Personnel trained in the handling of hazardous materials and equipped  with respiratory protection, (e.g., N95 disposable respirator), in accordance with the OSHA respiratory protection standard (29 CFR 1910.134), is recommended. Gloves and eye protection should be worn.  The work area and areas directly adjacent should be covered with a plastic sheet(s) and taped before remediation, to contain dust/debris.  Seal ventilation ducts/grills in the work area and areas directly adjacent with plastic sheeting.  The work area and areas directly adjacent should be unoccupied.   Further  vacating of people from spaces near the work area is recommended in the presence of infants (less than 12 months old), persons having undergone recent surgery, immune suppressed people, or people with chronic inflammatory lung diseases (e.g., asthma, hypersensitivity pneumonitis, and severe allergies).  Dust suppression methods, such as misting (not soaking) surfaces prior to remediation, are recommended.  Contaminated materials that cannot be cleaned should be removed from the building in sealed plastic bags. There are no special requirements for the disposal of mouldy materials.   The work area and surrounding areas should be HEPA vacuumed and cleaned with a damp cloth and/or mop and a detergent solution.  All areas should be left dry and visibly free from contamination and debris. If abatement procedures are expected to generate a lot of dust (e.g., abrasive cleaning of contaminated surfaces, demolition of plaster walls) or the visible concentration of the fungi is heavy (blanket coverage as opposed to patchy), then it is recommended that the remediation procedures for Level IV are followed.

Level IV - Extensive Contamination (greater than 100 contiguous square feet in an area)
A health and safety professional with experience performing microbial investigations should be consulted prior to remediation activities to provide oversight for the project. The following procedures are recommended:   Personnel trained in the handling of hazardous materials equipped with: full-face respirators with high efficiency particulate air (HEPA) cartridges; disposable protective clothing covering both head and shoes ; gloves.   Containment of the affected area: complete isolation of work area from occupied spaces using plastic sheeting sealed with duct tape (including ventilation ducts/grills, fixtures, and any other openings); the use of an exhaust fan with a HEPA filter to generate negative pressurization; airlocks; and decontamination room.    Vacating people from spaces adjacent to the work area is not necessary but is recommended in the presence of infants (less than 12 months old), persons having undergone recent surgery, immune suppressed people, or people with chronic inflammatory lung diseases (e.g., asthma, hypersensitivity pneumonitis, and severe allergies).   Contaminated materials that cannot be cleaned should be removed from the building in sealed plastic bags. The outside of the bags should be cleaned with a damp cloth and a detergent solution or HEPA vacuumed in the decontamination chamber prior to their transport to uncontaminated areas of the building.  There are no special requirements for the disposal of mouldy materials.  The contained area and decontamination room should be HEPA vacuumed and cleaned with a damp cloth and/or mop with a detergent solution and be visibly clean prior to the removal of isolation barriers.  Air monitoring should be conducted prior to occupancy to determine if the area is fit to reoccupy.

Level V - Remediation of HVAC Systems: A Small Isolated Area of Contamination (<10 square feet) in the HVAC System:
Remediation can be conducted by regular building maintenance staff. Such persons should receive training on proper clean up methods, personal protection, and potential health hazards. This training can be performed as part of a program to comply with the requirements of the OSHA Hazard Communication Standard (29 CFR 1910.1200).   Respiratory protection (e.g., N95 disposable respirator), in accordance with the OSHA respiratory protection standard (29 CFR 1910.134), is recommended.  Gloves and eye protection should be worn.  The HVAC system should be shut down prior to any remedial activities.  The work area should be covered with a plastic sheet(s) and sealed with tape before remediation, to contain dust/debris.  Dust suppression methods, such as misting (not soaking) surfaces prior to remediation, are recommended.   Growth supporting materials that are contaminated, such as the paper on the insulation of interior lined ducts and filters, should be removed. Other contaminated materials that cannot be cleaned should be removed in sealed plastic bags. There are no special requirements for the disposal of mouldy materials.  The work area and areas immediately surrounding the work area should be HEPA vacuumed and cleaned with a damp cloth and/or mop and a detergent solution.  All areas should be left dry and visibly free from contamination and debris.   A variety of biocides are recommended by HVAC manufacturers for use with        HVAC components, such as, cooling coils and condensation pans. HVAC  manufacturers should be consulted for the products they recommend for use in their systems.