BOSTON (CBS) – A carbon monoxide leak sent eight people to the hospital Saturday at a business across the street from Boston Common.

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Crews were called to the building at 28 Arlington Street Saturday afternoon around 2 p.m.

“Today at the spa, we had a number of calls for people who were sick and nauseous,” said Dennis Keeley, of the Boston Fire Department.

They evacuated the building, which houses Exhale Spa, along with condo units on the upper floors. A total of 30 people were checked out for possible carbon monoxide exposure.

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“We found a number of people with symptoms of carbon monoxide poisoning,” Keeley added. “The readings in the lower level were extremely high.”

The eight who were transported were taken to Tufts Medical Center and Mass. General Hospital.

Crews were still searching for the source of the carbon monoxide leak.

This is the second carbon monoxide incident this week in Boston.

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On Wednesday, seven people were hospitalized after a carbon monoxide scare at a Mattapan triple-decker.