without consideration of each of these elements exposes the investigator to possible professional malpractice law suits Building owners, tenants, attorneys, and insurance companies should look for the following when hiring a competent sick building investigator: credentials, experience, and client references. A strong investigating team should include industrial hygienists certified by the American Board of Industrial Hygienists, licensed professional mechanical engineers, and certified laboratory analysts and microbiologists. The sick building investigator should also be able to demonstrate relevant experience in solving sick building problems which can be substantiated with client references.