Lauren Roberts/Times Record News Wichita Falls police block entrances to the River Road Wastewater Treatment Plant Saturday evening. Two city workers from the plant were transported to Parkland Memorial Hospital in Dallas in critical condition after being exposed to a gas while making routine repairs in the facility's basement. Officials said the gas was never a threat to the public.
WICHITA FALLS, TEXAS
By John Ingle of the Times Record News
Investigators continue their work to determine what happened Saturday afternoon when two workers at River Road Wastewater Treatment Plant were exposed to hydrogen sulfide while working on a sludge pump.
The two employees were still at Parkland Memorial Hospital Sunday receiving treatment for chemical burns as a result of the incident. Authorities continue to piece together the events. The workers' conditions were not available Sunday afternoon.
Daniel Nix, utilities operations manager for Wichita Falls, said an employee with 18 years' experience another worker with more than a year at the plant were conducting routine maintenance on the pump when they were exposed to the dangerous gas. He said personnel at the plant who were performing a routine check on the workers found them down at about 5 p.m. and followed procedures for emergency response by the fire department and police department.
"The procedure is in extreme hazardous environment, they aren't to go in and rescue," he said, adding it would potentially add to the number of employees having to be rescued.
Nix said employees followed protocol and praised the fire and police departments for their response.
Working in utilities, whether at the River Road plant, one of the two water treatment plants or in the field is inherently dangerous work, Nix said. He said the last time an incident occurred was about 30 years ago. Saturday's incident was an unlikely event.
"It's one of those things the occasion for it to occur is there, but an incident actually happening is low," Nix said. "We work in a hazardous environment every day."
Nix said staff at the plant are understandably shaken up by the incident. He said they are a close-knit family and are concerned about the men's well-being.
Hydrogen sulfide
Chemical Compound
Hydrogen
sulfide is the chemical compound with the formula H
2S. It is a colorless gas with the characteristic foul odor of rotten
eggs; it is heavier than air, very poisonous, corrosive, flammable, and
explosive.
Formula: H2S
Molar mass: 34.0809 g/mol
Boiling point: -76°F (-60°C)
Melting point: -115.6°F (-82°C)
Density: 1.36 kg/m³
Classification: Sulfide, Sulfur compounds
Hydrogen Sulfide (H2S)
Hydrogen sulfide is a colorless, flammable, extremely hazardous gas with a “rotten egg” smell. It occurs naturally in crude petroleum and natural gas, and can be produced by the breakdown of organic matter and human/ animal wastes (e.g., sewage). It is heavier than air and can collect in low-lying and enclosed, poorly ventilated areas such as basements, manholes, sewer lines and underground telephone/electrical vaults.
Detection by Smell
- Can be smelled at low levels, but with continuous lowlevel exposure
or at higher concentrations you lose your ability to smell the gas even
though it is still present.
- At high concentrations – your ability to smell the gas can be lost instantly.
- DO NOT depend on your sense of smell for indicating the continuing presence of this gas or for warning of hazardous concentrations.
Health Effects
Health effects vary with how long, and at what level, you are exposed. Asthmatics may be at greater risk.
- Low concentrations – irritation of eyes, nose, throat, or respiratory system; effects can be delayed.
- Moderate concentrations – more severe eye and respiratory effects, headache, dizziness, nausea, coughing, vomiting and difficulty breathing.
- High concentrations – shock, convulsions, unable to breathe, coma, death; effects can be extremely rapid (within a few breaths).
Before Entering Areas with Possible Hydrogen Sulfide
- The air needs to be tested for the presence and concentration of hydrogen sulfide by a qualified person using test equipment. This individual also determines if fire/explosion precautions are necessary.
- If gas is present, the space should be ventilated.
- If the gas cannot be removed, use appropriate respiratory protection and any other necessary personal protective equipment (PPE), rescue and communication equipment. Atmospheres containing high concentrations (greater than 100 ppm) are considered immediately dangerous to life and health (IDLH) and a selfcontained breathing apparatus (SCBA) is required.