WICHITA FALLS, TX - NewsChannel 6 is learning more information about an accident in early July involving two Wichita Falls city workers who were found unconscious after attempting to fix a valve in the basement of the Wastewater Treatment Plant.
The city of Wichita Falls sent Newschannel 6 a copy of the Wichita Falls independent internal investigation by Freese and Nichols who were contracted to look into what caused high levels of Hydrogen Sulfide (H2S) to build up while Daniel Arredondo and David Sheppard were working on July 2nd.
According to the report, Arredondo and Sheppard inhaled health hazardous levels of the deadly H2S gas while in the primary pump station. The company tested four different theories about what could have caused such a large buildup H2S. Theory Four of the report located on page seven suggested that water conservation combined with increased human waste and high wastewater temperatures could have contributed to the dangerous levels of gas.
Page two of the report indicates that HS2 gas in certain concentrations can cause a variety of health symptoms from noticeable odor (0.11-1.5 parts per million) to nearly instant death(1,000-2,000 parts per million.) The report indicates that Arredondo and Sheppard were wearing protective breathing gear when entering the basement of the Wastewater Treatment Plant. However, when the two men were found their breathing gear was not on their person.
After Arredondo and Sheppard were removed from the basement Wichita Falls city meters indicated that the concentration of H2S was at least 500 parts per million) enough to cause staggering, eye damage, and death after exposures between 30 minutes to an hour.