A Boston-area hospital is investigating after five nurses who have worked on the same floor have developed brain tumors.

Mass General Brigham Newton-Wellesley Hospital said that in total, 11 employees from the fifth-floor maternity unit identified health concerns. Five had brain tumors, all of which are benign. Two of those have the most common, benign type — meningioma, according to the hospital in Newton, Massachusetts, which is about 10 miles west of Boston.

“The investigation found no…