Exposure to high levels of indoor toxic mold or black mold can lead to a multitude of illnesses or symptoms, especially in children, the elderly or those with compromised immune systems. If you, your family members or coworkers are affected by what seems like respiratory trouble in your commercial, residential or rental property, and you see something that looks like mold, you may want to have the air in that area tested. Some persons are affected by mold of low levels, some only by high levels, and some not at all. However, even for those not allergic, the mycotoxins produced by toxic mold can cause medical issues.