About 20 patients and staff were evacuated from a hospital in Exeter, N.H., on Friday and treated for dizziness, nausea and vomiting, a hospital spokesperson said.

By midday, officials at Exeter Hospital had yet to determine what caused the problems, which began between 8:30 a.m. and 9 a.m. when five staff members complained of feeling dizzy, spokesperson Debra Vasapolli said.

Patients and other staff members in the hospital’s operating room later became ill, she said. “No source has been determined at this point,” Vasapolli said.

“In an abundance of caution … we evacuated the [operating room] and closed it, as well as the emergency department, until we can determine the source.”

The affected staff and patients were being treated in the parking lot and on grassy areas outside the hospital, which is about 80 kilometres north of Boston, and were being sent to a number of other facilities, Vasapolli said.

The fire department in neighbouring Kingston said it sent two ambulances to the scene.