National Wildfire Coordinating Group

Hydrogen Sulfide Gas



Oil and gas production across the western United States has increased dramatically and can have an impact on fire suppression operations and expose fire personnel to health hazards. Many parts of the western United States also have natural occurring coal seams that can produce potentially toxic gases as well.

  • Fire personnel can be exposed to hydrogen sulfide gas (H²S) which is commonly expelled during oil and gas extraction operations and some coal seam seeps. H²S is a highly toxic, flammable, colorless gas produced by decaying organic matter and has a characteristic odor of rotten eggs at low concentrations; however, the sense of smell is paralyzed at airborne levels above 50 to 150 ppm. At higher concentrations, H²S can result in respiratory paralysis, asphyxial seizures, and death. Characteristics of a fatal exposure are rapid knock down, respiratory depression, tremors, blurred vision, cyanosis, seizures, and tachycardia. H²S vapor can also travel considerable distances to a source of ignition and flash back explosively, giving off corrosive and poisonous oxides of sulfur upon combustion.

To avoid exposure to H²S, here are some DO’s and DON’Ts concerning fire operations near oil and gas operations:


  • If you are responding to a known oil and gas pad or coal seam areas, DO contact local petroleum engineer or resource advisor.
  • If your unit has known oil and gas operations or coal seams, DO ensure that every firefighter is provided with training on H²S.
  • If you happen upon a remote oil and gas pad area, DO cordon off the area with flagging, deny entry, and modify suppression tactics to avoid the area.
  • DO avoid low-lying drainages, ravines, and gullies near oil and gas pads and coal seams as they tend to accumulate higher air concentrations of potentially toxic gases, especially during early morning hours when air has the tendency to sink.
  • If you suspect that someone has been exposed to H²S, DO seek medical care immediately at the nearest hospital.


  • DON’T locate fire camps, Incident Command Posts (ICP), or helispots on or near oil and gas pads.
  • DON’T depend on sense of smell for warning – H²S causes rapid deterioration of sense of smell.
  • DON’T attempt fire suppression on or near oil and gas pads. Local petroleum engineers or resource advisors may recommend safe working distances, and firefighters may also be given H²S monitors when working near oil and gas pad operations and/or coal seams.
  • DON’T wait to seek medical attention if H²S exposure is suspected.


Firefighter Health & Safety
Page Last Modified / Reviewed: 
Mar 2022

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