One of the first signs of a mold problem is a characteristic musty odor. It’s like the smell of a library full of old books, but can be more noxious. However, some molds do not give off odors. Mold growth can also be detected with the naked eye, but can easily be mistaken for dirt. You may also find out about mold if you have otherwise unexplained health and respiratory problems. If you find mold in your home or business, you can perform tests that can be purchased at the hardware store. However, these may not be 100 percent reliable. If the problem is serious, professional mold testers and remediation contractors can run a series of tests to precisely identify the size and scope of the problem. How dangerous is mold? Most molds aren’t dangerous to humans, but the U.S. Centers for Disease Control reports that there is sufficient evidence to link indoor mold exposure to respiratory problems among generally healthy people. Extended periods of exposure to mold can cause problems that are even more serious.