Shortly after 8:30 p.m. on Wednesday night, the Loudoun County Emergency Communications Center was contacted about a reported gas leak in the 22400 block of Sous Vide Lane in Sterling, which in fact turned out to be an ammonia leak.
Fire and Rescue crews from Loudoun County, Fairfax County, Prince William County, and the Metropolitan Washington Airports Authority all responded, and found that several employees had been exposed, some of whom were still being treated and evaluated a day later.
Of the 287 employees working in the facility at the time of the leak, a total of 33 patients were transported to area hospitals: five in serious condition, 17 in serious but non-life-threatening condition, and 11 with minor symptoms, officials said.
The remaining 254 employees were isolated, evaluated, and did not require treatment.
On Thursday, investigators said that a failed valve was the cause of the leak.
"As ammonia poses a significant inhalation hazard that can cause respiratory issues as well as burns on the skin, fire crews donned their protective equipment to perform a rapid primary search of the structure," a Loudoun County Fire and Rescue spokesperson said. "The search confirmed that everyone was out of the building.
"The Hazardous Materials team personnel then donned specialized protective garments and gear to enter the structure to isolate and control the leaking valve."
According to the Centers for Disease Control and Prevention, "exposure to high levels of ammonia in air may be irritating to your skin, eyes, throat, and lungs and cause coughing and burns.
"Lung damage and death may occur after exposure to very high concentrations of ammonia. Some people with asthma may be more sensitive to breathing ammonia than others."
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