VOCs are volatile organic compounds. Many household products and building materials contain VOCs and emit them as gasses over time through a process called off-gassing. According to the EPA, VOC can contribute to poor indoor air quality and can cause headaches and irritation of the eyes, nose and throat, among other symptoms. Some adhesives contain VOCs as a solvent, and they release VOCs into the air as they harden. When indoor air quality is a concern, look for adhesives that contain a lower number of grams of VOC per liter, or no VOCs at all. In general, there's little or no VOC content in hot melt adhesives, reactive adhesives and water-based adhesives.