They pose a cancer risk if this is where you keep your cleaning products. They may be unhealthy because of, again, formaldehyde. The average home has more than 60 toxic chemicals to which people are exposed on regular basis. The hazardous fumes often come from cleaning products. The most dangerous ones are those that contain chlorine and ammonia because mixing the two creates chloramine, a deadly toxic gas. Ingredients in common household products have been linked to asthma, cancer, reproductive disorders, hormone disruption, and neurotoxicity, according to the Environmental Working Group (EWG).