Post Office annex

Baltimore City fire vehicles respond to the downtown delivery annex of the Post Office on Colvin Street, where workers were evacuated because of carbon monoxide fumes. (Sun photo by Barbara Haddock Taylor / August 6, 2012)

A carbon monoxide incident closed an annex at Baltimore City's Main Post Office Monday and sent two people to University of Maryland Shock Trauma Center. Fire crews responded at about 8:30 a.m. to the one-story annex at Colvin and Lexington streets, near the main building in the 900 block of East Fayette Street. They found one person who had suffered a head injury from a fall and several other employees complaining of dizziness. A hazmat unit conducted air monitoring and determined that there were 38 parts per million of carbon monoxide inside the 35,000-square-foot building.

"That level would not be lethal, but, if exposed for any length of time, could cause nausea and dizziness," said Chief Kevin Cartwright, fire department spokesman.

The building incurred a power outage in the early morning hours that caused back-up generators to kick on and maintain utilities. Breezy conditions and the open bay doors may have drawn fumes from the generators into the building, Cartwright said.

In all, rescue crews evaluated 58 employees. Two, including the person with the head injury, were sent to the hospital, where their arterial blood gases will be evaluated, he said. The fire department originally reported that eight people were being treated and transported. By 10 a.m., CO levels inside the building were near zero, he said.

"Once the zero level is confirmed, our job here is done," Cartwright said.

Mary.gail.hare@baltsun.com.

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