Mold and Mildew Another issue related to carpet cleaning is the potential for mold growth in carpets that do not dry quickly enough. Steam cleaning carpets can thoroughly dampen the carpet AND the pad underneath. In humid or poorly ventilated spaces, a steam-cleaned carpet is an invitation for mold spores to sprout. Once mold begins to grow in a carpet or its pad, it’s impossible to remove adequately. The spores and particles will be embedded and will thwart any removal process unfortunately. Even when mold is not actively growing, mold particles and spores can cause health problems, such as fatigue, headaches, allergy symptoms, asthma attacks and other breathing problems.