Some species belonging to the fungal genera Aspergillus and Penicillium are known to be toxigenic or allergenic. Therefore, when lab results indicate an elevated level of Aspergillus/Penicillium spore counts in the air occupants may panic. It is important to know that although Aspergillus and Penicillium are very common indoors, not all spores reported by labs as Aspergillus/Penicillium belong to these toxigenic moulds. For more details see our current newsletter at http://www.moldbacteria.com/newsletter.html or check on past issues of our newsletter for this topic.