In theory and in reality, exposed earth contributes a lot of water vapor into the crawl space air in a home. As the damp soil dries into the house, the water vapor moves upward into the home. In most climates where there are dirt crawl spaces, you can never dry the earth, and this invisible stream of water vapor goes on forever. This moisture will produce microorganisms like fungi (mold) and bacteria. There are several other ways water gets into a house. Groundwater seeps, leaks, and even rushes into many crawl spaces. Water enters under the footing, between the walls, through light in block walls, and through cracks in poured walls. It then collects in puddles, slowly evaporating upward into the house. Fungus (mold) and bacteria can cause pathogenic and allergic responses in people living in the house.

Moisture and carbon sources increase these pathogenic microorganisms. Most people do not think that fungi (mold) and bacteria are everywhere in your home and crawl spaces. It is important to note that air pollutants like fungus (mold) can cause asthma, allergic rhinitis, and common allergies that are attributed to induced air pollutants. An estimated 45 million Americans suffer from some type of allergic disease that could be related to fungus (mold). For example, fungi, like Aspergillus, Penicillium, Fusarium, and Stachybotrys, can produce chemical responses in the body caused by the production of Mycotoxins, which may induce severe allergic reactions.

Indoor air containing high levels of gram-negative bacteria has been recognized for years as causing profound health issues in humans and animals. These bacteria produce heat-stable lipopolysaccharides (LPS) – protein complexes which are called Endotoxins. These bacteria and their endotoxins are ubiquitous in soil, water, and moisture in crawl spaces. In theory, exposed soil and earth contribute a lot of water vapor into the crawl space. Inhalation of these airborne microorganisms is associated with the development of various clinical symptoms due to endotoxins and lipopolysaccharides (LPS).

When I was in Crossville and Fairfield, Tennessee, I was impressed by the number of homes that had the encapsulation of crawl spaces and thus preventing the continued growth of abnormal levels of fungi (mold) or bacteria. So thank God for encapsulation. I believe this is a start.

Dr. Theodore J. Passon, Jr., PhD., MT(ASCP), SM(AAM), BCLD(ABB) is the owner and technical manager of Pure Earth Environmental Labs, Inc.