If your family is showing signs of illness and you suspect it is due to your environment then lead poisoning may be the answer. However, there are a number of other culprits as well. For example, many older homes were built with poor ventilation and over the years develop leaks or other sources of moisture that can contribute to massive mold colonies. You may want to consider looking into mold inspections and testing as well as air quality testing to ensure the quality of the air inside your home isn’t making you sick.