APEX, NC – Over 17,000 residents of Apex, NC were evacuated from their homes on an early October morning after several explosions and a fire at a chemical plant released a chlorine cloud that rose 50 feet in the air. Although there is no word yet on what caused the fire, witnesses said there were 20 to 30 explosions inside the plant. More than 25 people were treated for respiratory distress, including 10 law enforcement officers and one firefighter. The plume could be seen and smelled for over two miles. Even the town's fire department and 9-1-1 Center had to be evacuated. Those residents not evacuated were advised to close all windows, turn off all air conditioning and be aware if they have tenderness of the mouth, gagging and nausea, which are typical signs of chlorine poisoning.

According to the Associated Press, a yellow haze lingered over downtown Apex and the air smelled faintly of chlorine as police lined the main street that runs through the town's business district, sealing off the area to prevent unauthorized entry.

Chlorine is a poisonous, corrosive, greenish yellow gas that is irritating to the eyes and respiratory system; it is two and a half times heavier than air so it tends to hang close to the ground when released from its containers, rather than dissipating in the air light lighter gases do. It was used as a choking agent during World War I. Industrial uses include water purification, sanitation, and the manufacture of some chemicals.

The incident occurred at the Environmental Quality Industrial Services. Apex is located about 10 miles southwest of Raleigh. The plant is a hazardous waste business and housed a variety of other chemicals, ranging from paints to solvents.

After assessing the situations, officials determined that the best course of action was to let the fire burn itself out in to avoid toxic runoff and the risk to firefighters. According to CNN, a hazardous materials team from Raleigh will assess the damage. The team will wear special protective suits and scale 90-foot ladders to better observe the disaster.

The Environmental Protection Agency reportedly sent three of its personnel, eight EPA contractors and two toxic specialists to the scene as well as air-monitoring and emergency response equipment.

Among those evacuated were 106 residents of a nursing home, who were taken to a local hospital. Other residents were sheltered in local hotels and an elementary school, which was transformed into an emergency shelter.

Initial air quality tests conducted the morning after the incident found nothing alarming, according to state environmental officials. The weather cooperated as a light rain began to fall, which had the effect of scrubbing the air, according to the state's Division of Air Quality. According to Mayor Keith Weatherly, "They were optimistic, and the quote was that 'the rain is the best thing that could happen.'" Mayor Weatherly also reported that "That plume that was moving around may not be issue any longer, so that is very good news."

For information on chlorine safety and emergency response to chlorine incidents, see Emergency Film Group’s award-winning HazChem program Chlorine.