Hydrogen sulfide gas dangers
Submitted by The Federal Fire and Aviation Safety Team
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 also 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, and gives 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 and deny entry and DO modify suppression tactics to avoid the area.
- DO avoid low lying drainage, 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 depend on sense of smell for warning as H²S causes rapid deterioration of sense of smell.
- DON'T attempt fire suppression on or in close proximity to oil and gas pads. The Local petroleum engineer or resource advisor 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.
For more safety tips from the Federal Fire and Aviation Safety Team, visit its Six Minutes for Safety section at www.nifc.gov.