Is dry rot a health hazard for 11 month baby?

Yes.

Dry rot is a type of wood decay caused by fungi that can cause structural damage to buildings. It can also produce toxic spores that can irritate the eyes, nose, and throat and even cause more severe health problems, such as asthma and bronchitis. Infants and young children are more vulnerable to these health effects because their lungs are still developing. As a result, it is important to take precautions to prevent dry rot in homes where infants and young children live.