Hydrogen sulfide is a toxic and flammable gas known by several different names including sewer gas, stink damp, swamp gas and manure gas. According to the Occupational Safety and Health Administration, the gas has a rotten egg smell and is colorless, flammable and hazardous. The gas can also exist as a liquid compressed gas. Without the proper safety equipment in place to detect hydrogen sulfide or other gas leaks, employees may be putting their workers at risk for suffering from overexposure.
Hydrogen sulfide occurs naturally in crude petroleum, natural gas and hot springs. OSHA said hydrogen sulfide is produced when bacteria break down organic materials and human and animal waste.
The oil and gas industry is surrounded by hydrogen sulfide as drilling and refining activities also produce the toxic gas, which can result in worker injury on the job site if exposure occurs.
Since the gas is heavier than air, it can travel along the ground and collect in low-lying and enclosed areas with poor ventilation. Areas especially susceptible to a buildup of hydrogen sulfide include basements, manholes, sewer lines, underground telephone vaults and manure pits.
The gas is highly flammable and can explode if the concentration in the air is between 4 percent and 45 percent. As a result of burning hydrogen sulfide, sulfur dioxide can be produced, according to the Centers for Disease Control and Prevention's Agency for Toxic Substances and Disease Registry (ATSDR).
The symptoms of hydrogen sulfide poisoning
The maximum exposure set by OSHA is 50 parts per million for 10 minutes with no other exposure.
Symptoms of acute exposure to the toxic gas include nausea, headaches, delirium, balance issues known as disturbed equilibrium, tremors, convulsions and skin and eye irritation. If workers inhale a higher concentration of hydrogen sulfide, rapid unconsciousness and death can occur. People also may suffer from frostbite if the liquid form of the gas is present. Irregular heartbeat can also result from overexposure to the gas.
Anyone who attempts to rescue an employee with overexposure symptoms should be alert of the hot zone. This area contains extremely high levels of hydrogen sulfide and can be fatal for anyone who attempts a rescue.
Employers should be cautious in exposing employees to hydrogen sulfide. A toxic gas detector can alert workers to the presence of dangerous gases and prevent injury or death.
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