Several nurses from same floor at Massachusetts hospital diagnosed with brain tumors

NEWTON, Mass. - A Massachusetts hospital said their facility is not posing an environmental risk after five nurses reportedly developed brain tumors after previously working in the same area of the building. 

What we don't know:

According to Boston 25 News, 11 nurses at Mass General Brigham Newton-Wellesley Hospital came forward late last year with brain tumor diagnoses.

According to the outlet, they worked in the hospital's labor and delivery department. Five cases were various types of benign tumors, and six cases were "other health concerns."

What we don't know:

It's not known what caused the brain tumors in the nurses. 

What they're saying:

The hospital put out a statement saying they launched an extensive investigation into the matter along with the Department of Occupational Health and Safety, Newton-Wellesley Safety Officer, radiation and pharmaceutical safety offices, and external environmental consultants. 

"The investigation found no environmental risks which could be linked to the development of a brain tumor," the hospital said in a statement to FOX Television Stations.  "We presented these findings to relevant stakeholder groups, including the staff on the unit and the Massachusetts Nursing Association, and have held forums to meet with clinical and Occupational Health leaders to answer their questions."

"The hospital provided the MNA with the test results from the investigation, including those of several external environmental firms," the statement continued, adding "the health and wellbeing of our staff, clinicians, and patients is our absolute top priority."

What's next:

The MNA told Boston 25 News it believes the hospital's investigation was inadequate and that it is conducting its own investigation, speaking with numerous present and former hospital staff members.