we have had an odor in our basement that smells like dead animal only when our dryer is on. My husband tore down the walls,nothing was in there, replaced dryer vent, we bought a new washer and dryer but the smell is still there. We looked in all the celling bays for dead mice nothing there . We have our own septic new x5 years ago. Any ideas outhere? We have a cement floor in the washer and dryer room. Thanks lin