Hydrogen sulfide, or H2S, is a life-threatening gas often naturally present in oil and gas deposits. According to the Occupational Safety and Health Administration, this hazardous gas is also a by-product of the process of desulfurization of oil and gas. Workers in the industry have a high risk from multiple arenas.
But just how dangerous is it, and how can workers protect themselves?
Symptoms of exposure
The National Institute for Occupational Safety and Health measures H2S in parts per million, or ppm. Workers may not notice typical background concentrations of 0.00033 ppm. At 0.01-1.5 ppm, many people notice a rotten egg smell, and this becomes stronger at 3-5 ppm. Prolonged exposure at this range could cause nausea, headaches and sleep problems. The following are effects at greater exposures:
- 20 ppm: Headache, irritability, dizziness, fatigue, poor memory
- 100 ppm: Eye inflammation, possible digestive upset, respiratory tract irritation after an hour of exposure
- 200-300 ppm: After one hour, serious eye inflammation and respiratory tract irritation, possible fluid in the lungs
- 500-700 ppm: Collapse in five minutes, serious eye damage in 30 minutes, fatal after 30-60 minutes
- 700-1,000 ppm: Collapse/unconsciousness within one to two breaths, fatal in minutes
- Over 1,000 ppm: Nearly instant death
People who inhale enough H2S to lose consciousness often have long-term effects such as headaches and poor motor function, as well as cardiovascular problems.
OSHA has set a permissible exposure limit of 20 ppm for general industry. To protect workers, employers should have policies, procedures and contingency plans for the presence of H2S. This includes always actively monitoring for H2S and providing extensive training programs for workers so they are able to identify potential for exposure, use safety techniques and equipment, recognize symptoms and perform proper rescue techniques.
If employers provide workers with the knowledge and equipment they need to stay safe, the risk of a harmful or fatal exposure event is much lower. Every worker has a legal right to a safe workplace.