The morning of Oct. 21, emergency officials reported that two chemical compounds were “unintentionally” mixed in a holding tank at the Horseshoe Bay Central Water Plant during a delivery.
The incident resulted in fumes and a cloud of gas which prompted officials to call for a shelter in place order due to possible toxic exposure.
At approximately 8:30 a.m. that morning, a delivery driver off-loaded approximately 4,000 gallons of aluminum sulfate into a tank of sodium hypochlorite, according to Horseshoe Bay Fire Chief Doug Fowler.
Approximately 9,000 gallons of sodium hypochlorite were in the tank before the delivery occurred, his alert continued.
Fowler told emergency management officials that the Texas Commission on Environmental Quality (TCEQ) was notified of a strong high concentration of chemicals at the water plant.
“The mixing of chemicals resulted in a chlorine cloud with dangerous levels within one block of the water plant,” Burnet County Emergency Management Coordinator Derek Marchio released in a report. “The chemical reaction released chlorine gas from the tank vent. This gas drifted in the south wind to the local area, burning eyes and causing nasal irritation.
“The tank was shut within minutes, but the off-gases continued to create an air exposure issue,” Marchio added. “As a result, a shelter in place order was issued at Cottonwood Shores and Horseshoe Bay and posted on social media. At approximately 10:30, the tank quit off gassing and the cloud began to disperse with a southerly wind.”
Areas to the southwest had no readings of gas by 11 a.m., he continued.
The following emergency email was sent to Horseshoe Bay residents:
“Police have begun going door-to-door to warn area residents affected by the gas to remain inside until the gas dissipates, which is expected to take approximately one hour. Hazmat crews have been notified, and clean-up will begin soon. More information will follow as it is available.”
By 11 a.m., officials reported that “the tank has stopped off gassing.” Officials continued a short time later that “… the gas cloud is dispersing and reaching safe levels around the site.”
By noon, Fowler informed emergency response officials that “Gas levels immediately around the plant have dropped to 0.1. They need to be dropped to .5 to be completely safe. HSB Fire is in the process of checking the neighborhood to the north (Lucy Ln. area). The neighborhood adjacent to the plant (Highlands Blvd.) has been deemed safe as well.”
As of press time, Oct. 21, residents awaited the latest details about the incident, however, conditions had improved.
