Health & Safety: Mythbusting Mold: Ten Facts You Should Know
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Contributors to this page: Tara Kennedy (Original Author), Kerith Koss Schrager
This article originally appeared as a special Health & Safety Article in AIC News--and may have been updated
Mythbusting Mold: Ten Facts You Should Know
Date: September 2015
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Mythbusting Mold: Ten Facts You Should Know
Mold is a ubiquitous concern in conservation (and elsewhere!). Since it is encountered frequently, it is important that conservators know the facts about it so that they can protect themselves. Some of these facts may be familiar to you, others not. Check out these ten tips and see what new facts you learn!
- All molds can pose a health risk to humans. Adverse reactions to mold can be a mild skin irritation; or can be severe for those with compromised immune systems. Both dormant and active mold can cause an unsafe reaction.
- Always wear appropriate Personal Protective Equipment (PPE) in any situation where you might encounter mold; you cannot predict how you will react. PPE should include not only respiratory protection, but eye (impermeable goggles) and skin protection (gloves, lab coats, sleeve guards). Your respirator should have N-95 or P-100 filters for filtration of mold spores and activated charcoal filters if odors are a problem. Be sure to get your doctor’s permission before using a respirator (even disposable ones), especially if you have asthma or other respiratory issues. Be certain to keep your fit test up to date, including getting your doctor’s permission.
- Surface molds – the molds that conservators usually encounter – produce conidia, which form and release mold spores into the air. Those spores float through the air and land on surfaces along with dirt, skin cells, pollen, fibers, and other materials that make up dust. Cleaning is your best bet for preventing mold, especially when it’s dormant. Removing the spores doesn’t give them the chance to germinate and colonize.
- For safe cleaning, be sure to use a HEPA or ULPA-filtered vacuum (variable suction is best) in a fume hood while wearing PPE. Dispose of mold-infested filters, vacuum bags, and other waste by sealing them in thick polyethylene bags and throwing them away with the trash.
- What is the key element in stopping the mold life cycle? Water availability! Water vapor in the air, water content of the mold, and the equilibrium moisture content and its availability within the substrate all contribute to the life cycle of mold. Controlling your environment by keeping your dew point below 50ºF and your relative humidity below 65% will reduce the possibility of spore germination.
- Mold spores are tough; with thick cell walls, mold spores are not defeated easily. Spores are designed to survive in an outdoor environment so that they do their job: breaking down dead organic matter such as fallen leaves and dead trees. Dormant conidia and spores can survive extreme heat, drought, and freezing temperatures.
- Active, germinated spores are more susceptible to destruction. Flash or quick freezing around 32ºF (0ºC) kills active mold spores from the inside out: the moisture in the cytoplasm in the spore turns into ice crystals. As the water expands (freezes), it causes the active mold spore to burst, breaking up the cell wall. Dormant spores should be removed through cleaning (see #4).
- The colored stains that you see on mold-infested objects are pigments excreted by the actively-growing hyphae of the fungus and/or the pigment in the hyphae that penetrate the substrate. Hyphae are the long, branch-like structures of a fungus that are its main mode of vegetative growth. The pigments are present to help protect the mold cells from radiation (IR, visible, and UV).
- One element found in molds is mycotoxins. A class of mycotoxins – known as trichothecenes – has been implicated as potentially infecting humans via inhalation rather than ingestion or dermal contact. One of the molds that produces this mycotoxin is Stachybotrys chartarum, named in the media as “toxic black mold.”
- Did you know that the AIC’s Health and Safety Committee has access to safety resources? If you are a conservator in private practice, or your institution doesn’t have an environmental health and safety department, ask us for assistance to point you in the right direction! Have a question about health and safety in your conservation work? Send it to us at [email protected] Additional Health & Safety resources are available on the Health & Safety Committee website and wiki.
Fancy yourself a mold expert? Try this online identification quiz (warning: this is a medical site so some of the pictures are a bit gross)
A Brief Guide to Mold, Moisture, and Your Home. Environmental Protection Agency (EPA).
Facts about Mold. American Industrial Hygiene Association (AIHA)
Fungal Biology: Welcome Page. Fungal Biology.
Fungal Facts: Solving fungal problems in heritage collections. Florian, Mary-Lou. 2002. London: Archetype.
Health Professional: Mold Frequently Asked Questions. Wisconsin Department of Health Services.
Indoor fungal infestations and mycotoxicity: guidance for public health professionals and industrial hygienists. Thiboldeaux, Robert, PhD.
Magenta pigment produced by fungus. Chiba, Sanae et al. 2006. Journal of General Applied Microbiology 52: 201-207.
Mold: Basic Facts Centers for Disease Control and Prevention (CDC)
Mold Remediation Guidelines. North Carolina State University Environmental Health and Public Safety Center.
Mold Resource Center, American Industrial Hygiene Association (AIHA)
Mycology Answers. Isaac, Susan. 1994. Mycologist 8: 178-179.
Occupational Safety and Health Administration Quick Card: Protect Yourself. Respirators. Occupational Safety and Health Administration (OSHA), United States Department of Labor.
Safety and Health Topics: Mold. Occupational Safety and Health Administration (OSHA), United States Department of Labor.
[http://ntp.niehs.nih.gov/ntp/htdocs/chem_background/exsumpdf/stachybotrys_508.pdf Stachybotrys chartarum (or S. atra or S. alternans) Review of Toxicological Literature.] National Institute of Health (NIH)
Tree of Life Web Project.
Using Filtering Facepiece Respirators. Health & Safety Committee (American Institute for Conservation). 2015.
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