By Timothy Mucciante, eHow Contributor
Particular Hazards For Pregnant Women
Besides the ammonia smell coming from the cat urine, cat feces can also be a danger. Feces contain toxoplasmosis, a bacterium that can cause illness. If this disease is passed onto a pregnant woman, her baby may suffer from birth defects like mental retardation. The child being stillborn is the worst case scenario. Toxoplasmosis is a disease that can be spread from cats to humans. However, simply smelling cat urine coming from a litter box does not pose any greater danger to a pregnant woman.
Environmental Protection Agency
The EPA has classified ammonia as a toxic chemical and requires notification to a community when there is an abnormally high concentration of ammonia in the area. Ammonia is colorless, but has a truly distinct and foul odor at concentrations of 50 parts-per-million. Repeated exposure to ammonia, even of lesser concentration, can cause pneumonia, bronchitis, eye damage and skin cancer.