Most people have some experience with mold, but what does toxic mold look like? The black gunk in a window frame, the moldy smell in a damp basement, or the fuzz on food left in the fridge for too long. Not all molds are inherently harmful. Some strains of mold are common outdoor molds found in nature, serving a critical purpose for the planet. They aid in the decomposition of the planet and are a natural part of nature’s cycle of regeneration and recycling (check out the Netflix documentary Fantastic Fungi – it’s great!). But in large quantities, mold can make a susceptible person very sick. Only about 25% of the population is mold sensitive, so it’s quite common for only one person in a house to get sick from mold. What is toxic mold? The most common cause of mold toxicity is from water-damaged buildings. The mycotoxins that result from water damage are pathogenic, or disease-causing, to humans. They are poisonous and can be deadly. Some of these mycotoxins – trichothecenes in particular – have even been studied as chemical warfare agents.