Mold in the Workplace Basic Information
&What to Do About It
Shawn HolleSafety AnalystDPH/OSH
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Agenda
What is Mold? What Does Mold Need to Grow? Examples of Mold in Buildings Cleanup Approaches Personal Protective Equipment (PPE) Potential Health Issues?
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What is Mold?
Mold is a variety of fungus (a plant): Range From Single Cells to Mass Growth
Examples: Mushrooms, Shower Mold
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What Does Mold Need to Grow?
Constant Temperature: Between 60°F to 105 °F Oxygen Food Sources:
Carbohydrates, Starch (Think Wall Board)
Organic Debris Constant Moisture (Liquid Water)
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Examples of Mold Growth in Buildings
Water + Food = Mold Growth. Most Building Materials are Potentially a Food
Source
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1. Gravity: Rain
2. Air Movement: Heated air rises to
the attic. Heated air carries moisture vapor with it. Vapor condenses when in contact with unheated.
Water Movement
roof leak
water wicking up end grain
low pressure
high pressure
water molecule
air molecule
flow of air and water
bulk moisture capillary action
vapor diffusion air-transported moisture
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Basic Moisture Terms
Relative Humidity: Ratio of water vapor in air to total amount of water vapor air can hold (Warm air holds more water vapor than cold air does).
Saturated Air: 100% humidity. Air cannot hold any more water vapor.
Condensation: When water vapor turns into liquid Dew Point: Temperature at which water vapor
condenses from gas to liquid.
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Inside Moisture
Additional Sources:
Pets, aquarium, houseplants, humidifiers, exposed soil in crawl space, malfunctioning gas or oil appliances, construction moisture, unvented space heaters.
Breathing:
2.88 lb/day per person
Laundry:
Drying clothes (if not vented to the outside) 1lb/each lb of clothes.
Bath:
.12 lb/each per bath
.5 lb/each per shower
Kitchen:
Mopping floor (10’ x 10’ room) 3 lb… Cooking (gas) 4.7 lb/day… Cooking (electric) 2 lb/day…Dishwashing 1 lb
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Carpeting / Flooring
Mold Growth Beneath Wood Floor
Carpet Infested With Stachybotrys chartarum
Concrete Moisture Trapped
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Flooring
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Flooring
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Outdoor Moisture: Precipitation & Soil Contact
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Roof
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Roof
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Roof:Penetrations
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Windows & Door Openings
Air leaks in where window
sash slides past frame: weather-
strip here
Air leaks in where window casing meets
wall: caulk here
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Windows & Door Openings
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Windows & Door Openings
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Plumbing
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PlumbingUnder the Toilet
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Plumbing
Floor Framing
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HVAC Systems
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Lath & Plaster (Stucco)/CladdingBehind the Drywall
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Lath and Plaster (Stucco)/Cladding
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Personal Protective Equipment (PPE)
Choose PPE on Case by Case Basis
Call DPH OSH for Guidance (415)554-2736
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Cleanup Approaches
Identify Water Source Repair Area and Prevent Water Intrusion Clean Surfaces (3 applications minimum) Dry Surfaces Thoroughly Repeat as Necessary
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Potential Health Effects?
Some Varieties Can Cause Allergic Reactions in Sensitive Individuals
May Provoke Asthma Attack in Allergic Individuals
Irritate Eyes, Nose, Throat, & Lungs Potentially Toxic Effects Rare
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Toxic Mold:Potential Health Effects?Recent Study Conclusions
Population Prevalence of Mold Related Allergic Respiratory Symptoms ==5%
Other Serious Allergic Conditions Rare Outdoor Molds Generally More Important Than
Indoor Molds Indoor Molds Should Be Remediated After
Addressing Moisture Sources Stachybotrys Chartarum Has Not Been
Demonstrated to Be a Particularly Harmful Mold