A security guard at the National Aquarium passed out early today when he walked into a room where machinery that produces ozone for a water purification system had blown a pressure relief valve.
The guard, Sylvester McIntosh, 38, of the 3500 block of Edmondson Ave., was taken to Mercy Medical Center, where he was reported in stable condition, undergoing evaluation.
Capt. Patrick P. Flynn, a spokesman for the city Fire Department, said a hazardous materials team was called to the aquarium's new Marine Mammal Pavilion at 6:41 a.m., but aquarium personnel had controlled the leak before they arrived.
David Pittenger, senior director for programs at the aquarium, said that when the pressure relief valve blew about 6 a.m., computers alerted a filtration technician, who opened a fire door to air out the room.
That set off a security alarm and brought the guard, who walked into the room to check the door.
"He got a good whiff of ozone, and initially he felt a little light headed," Pittenger said. The guard soon passed out, however, and "that's when security called the emergency equipment."
Under normal operations, he said, ozone used at the aquarium is not dangerous to aquarium-goers.
It is an unstable form of oxygen. The aquarium generates it at the pavilion from regular air. It is used in place of chlorine to purify water in the pavilion's marine mammal tanks because it is "typically much safer for animals and people."
It changes quickly back into oxygen but can be harmful if breathed in high concentrations or for long periods of time, Pittenger said.
The pressure relief valve that blew this morning has blown once before, he said.
"That's typical in a shake-down situation, with a new facility and new equipment," he said. "But this shouldn't be happening now that we have people in the building. We're going to get the manufacturer down here right away."