A sixth staff member at Massachusetts General Brigham’s Newton-Wellesley Hospital has been diagnosed with a brain tumor, adding to growing concerns among workers on the same floor.

This latest diagnosis follows several other similar cases among staff, primarily nurses, on the fifth floor of the hospital, located just outside of Boston. Despite the alarming pattern, hospital officials maintain that no environmental risks have been identified in the area.

Earlier this month, the news broke that multiple employees working in the maternal care labor and delivery unit had developed brain tumors, prompting an investigation.

According to one nurse who spoke with CBS News, as many as 10 staff members, both current and former, have been affected by brain tumors in recent years. “It’s getting to the point where the number just increases, and you start saying, ‘Am I crazy thinking this?’” she remarked. “This can’t just be a coincidence.”

The tumors diagnosed in all six staff members have been benign, but the hospital’s inability to pinpoint a cause has raised further concerns. In response to the growing number of cases, the hospital conducted an investigation, working with the Department of Occupational Health and Safety, Newton-Wellesley Safety Officer, and various external environmental consultants.

“We conducted an extensive investigation in collaboration with several external experts,” the hospital said in a statement to NBC10 Boston. “The investigation found no environmental risks which could be linked to the development of a brain tumor.”

Officials also clarified that, at the time, only five staff members—four nurses and one former nurse—had been diagnosed with brain tumors. Six additional staffers on the fifth floor were found to have “other health concerns,” but the nature of those issues has not been disclosed.

However, the hospital’s findings have not satisfied the Massachusetts Nurses Association, which has expressed skepticism about the investigation’s thoroughness. “They only spoke to a small number of nurses, and their environmental testing was not comprehensive,” a representative told Boston.com. “The hospital cannot make this issue go away by attempting to provide a predetermined conclusion.”

Meanwhile, a nurse who initially raised concerns about the number of brain tumor cases believes the true total may be higher than reported. She emphasized that the hospital has not provided adequate support to affected staff, many of whom have had to undergo surgery as a result of their tumors. “We want reassurance, because this has not been a reassuring past few months for a lot of the staff members,” she said. “We want to feel safe, the same way we want to make our patients feel safe.”

Despite the ongoing concerns, the hospital has reassured staff that their health and safety remain top priorities. However, as more staff members continue to come forward with similar diagnoses, the situation remains under scrutiny, with many questioning whether the hospital’s investigation fully addresses the potential risks.

As the hospital navigates this troubling situation, both the affected staff and the public are left wondering if more comprehensive testing is necessary to uncover any hidden risks on the fifth floor.