text: Mold health issues refer to the harmful health effects of molds ("moulds" in British English) and their mycotoxins. However, recent research has shown these adverse health effects are caused not exclusively by molds, but also other microbial agents and biotoxins associated with dampness, mold, and water-damaged buildings, such as gram-negative bacteria that produce endotoxins, as well as actinomycetes and their associated exotoxins. Approximately 47% of houses in the United States have substantial levels of mold, with over 85% of commercial and office buildings found to have water damage predictive of mold. As many as 21% of asthma cases may result from exposure to mold. Substantial and statistically significant increases in the risks of both respiratory infections and bronchitis have been associated with dampness in homes and the resulting mold.
  Molds and many related microbial agents are ubiquitous in the biosphere, and mold spores are a common component of household and workplace dust. While the most molds in the outdoor environment are not hazardous to humans, many found inside buildings are known to be. Reaction to molds can vary between individuals, from relatively minor allergic reactions through to severe multi-system inflammatory effects, neurological problems, and death. The United States Centers for Disease Control and Prevention (CDC) reported in its June 2006 report, Mold Prevention Strategies and Possible Health Effects in the Aftermath of Hurricanes and Major Floods, that "excessive exposure to mold-contaminated materials can cause adverse health effects in susceptible persons regardless of the type of mold or the extent of contamination." Mold spores and associated toxins can cause harm primarily via inhalation, ingestion, and contact. In higher quantities such as those found in water-damaged buildings, they can present especially hazardous health risks to humans after sufficient exposure, with three generally accepted mechanisms of harm and a fourth probable mechanism:
  # Allergic reactions, including allergic bronchopulmonary aspergillosis
  # Invasive mold infections (mycosis)
  # Toxicity (poisoning by mycotoxins)
  # Innate immune dysfunction.