Five Severna Park homes were evacuated as a precaution yesterday as firefighters contained a leaky chlorine tank at a water-treatment plant.
Workers at the Severndale Water Treatment Plant, 123 Southway, called 911 at about 11:30 a.m. after discovering the leak while replacing a nearly empty, 150-pound chlorine tank with a fresh tank.
The workers sealed off the 10-foot by 20-foot room before evacuating the plant, said Battalion Chief Matthew Tobia, a county Fire Department spokesman.
Chlorine is a chemical asphyxiant, a substance which can lower oxygen levels, that can be harmful to humans, Chief Tobia said.
As such, firefighters responding to the call used an abundance of caution. The five closest homes to the plant were evacuated and other residents were asked to stay inside.
Chief Tobia said tests outside the building showed no chlorine gas in the air, so neighbors didn't have to shut their doors and windows. Pedestrians were allowed on most of the street while firefighters worked, although cars were blocked from driving on the road.
Hazardous materials crews from Jones Station and the Annapolis Fire Department sealed off the tank and vented the room.
Two firefighters donned neon yellowish-green protective suits to enter the building shortly after 1 p.m. Firefighter Jimmy Johnston from Jones Station and Firefighter John P. Smith of Annapolis used a special clamp called an "A kit" to seal off the leaky tank.
Because the room had high levels of chlorine, the firefigthers used special breathing apparatus.
They had the tank sealed off by about 1:30 p.m. Once the building was aired out, it was turned back over to the county Department of Public Works. A contractor for the county was expected to pick up the tank.
After they finished, the firefighters were doused with water to convert any chlorine to a harmless substance.
Airing out the building wasn't dangerous, because the cool air and light breeze meant the chlorine gas would dissipate quickly, Chief Tobia said.
Exposure to low levels of chlorine can cause eye, nose and throat irritation. Exposure to higher doses can cause coughing, breathing problems and lung damage, according to the federal Agency for Toxic Substances and Disease Registry. It also is converted to a harmless substance when it reacts with water.
When chlorine is used in treating drinking water, it is usually turned into other chemicals before being added to water, according to the agency.
The county Fire Department deals with a handful of chlorine leaks each year, Chief Tobia said.
