At least 12 people with symptoms of illness were reported at Johns Hopkins at Keswick in North Baltimore on Monday, almost a week after nearly two dozen people fell ill from a contaminated water source at the hospital and university system's administrative complex.
Again, personnel with the Baltimore Fire Department descended on the two-building complex, with multiple medics, a fire engine and a hazardous-materials unit responding, said Chief Kevin Cartwright, a department spokesman.
The health department also responded, said spokeswoman Tiffany Thomas Smith, as did emergency response officials and a team from Johns Hopkins Hospital.
"It's the same team as last week," Smith said.
Two calls were received by city emergency dispatchers from the complex between 10 a.m. and 11 a.m., and two more within about 10 minutes of each other, both about 2:30 p.m.
An additional eight people experiencing symptoms were identified during the afternoon, officials said.
All patients were light-headed and experiencing headaches, weakness, nausea and dizziness, Cartwright said.
Seven were transported to area hospitals, and at least four refused medical treatment, officials said. The complex was not evacuated.
Last Tuesday, about 600 people were evacuated from the complex's south building after nearly two dozen began experiencing headaches, difficulty breathing and dizziness. The south building will be closed Tuesday as Monday's incidents are further investigated.
An investigation into the illnesses, which sent many to the hospital, determined the cause to be contamination of the drinking water by chemicals known as nitrates and nitrites. The contamination occurred somehow in the boiler room's water heating system. The chemicals can cause low blood pressure and a disorder that makes it difficult for the body to deliver oxygen to organs and tissue — the results of which can be deadly.
The complex was closed for two days as health officials analyzed the contamination.
"It's going to take some more testing for us to say how it became a source," Smith said last week of the water heater. "We have isolated it as a source."
On Monday evening, Smith said officials were "conducting tests of the water supply at multiple locations throughout the south building."
Cartwright said he did not know whether the illnesses reported Monday were caused by the same chemicals blamed for last week's illnesses.
"It could be relevant, may not be," he said.
He said a hazardous-materials unit had ruled out other causes such as carbon monoxide after sweeping the building with detectors.
Hopkins officials wrote on the Johns Hopkins at Keswick website that they would provide updates to employees as information becomes available.
The complex houses more than 1,000 employees, and had reopened Thursday with some sinks, restrooms and other water sources shut down. Officials had said the water heater identified as the problem last week would be replaced.