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Hydrogen Sulfide Gas (H²S)

Hydrogen sulfide (also known as H²S, sewer gas, swamp gas, stink damp, and sour damp) is a colorless gas known for its pungent "rotten egg" odor at low concentrations. It is extremely flammable and highly toxic. 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. Naturally occurring coal seams can produce potentially toxic gases as well.
Hydrogen sulfide is used or produced in a number of industries, such as:

  • Oil and gas refining
  • Mining
  • Tanning
  • Pulp and paper processing
  • Rayon manufacturing

Hydrogen sulfide also occurs naturally in sewers, manure pits, well water, oil and gas wells, and volcanoes.
At higher concentrations, H²S can result in respiratory paralysis, asphyxia, seizures, and death. Characteristics of a significant exposure are rapid knock down, respiratory depression, tremors, blurred vision, cyanosis, seizures, and elevated heart rate. 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:

Do's:

  • 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'ts:

  • 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.

 

Category
Firefighter Health & First Aid
References
Maverick Lessons Learned Review
NWCG Incident Response Pocket Guide, PMS 461
Interagency Standards for Fire & Fire Aviation Operations (Red Book)

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NWCG Committees Observe Suicide Prevention Awareness Week: September 7-13, 2025

Date: Sep 5, 2025
Questions? Please contact:
Mental Health Subcommittee

The NWCG Mental Health Subcommittee (MHSC) and Risk Management Committee (RMC) recognize the unique challenges and demands faced by the wildland fire community. The MHSC and RMC know that we are all stronger together and believe in fostering a culture of support, understanding, and resilience.

Suicide Prevention Awareness encourages us to actively connect with and support each other. For more information that could make a difference for yourself or someone else please review the materials and resources provided for the 2025 Suicide Prevention Awareness Week.

References:

2025 Suicide Prevention Awareness Week Materials and Resources

NEW! Incident Performance and Training Modernization Story Map Now Available

Date: Aug 26, 2025
Questions? Please contact:
National Wildfire Coordinating Group

NWCG is excited to announce the launch of the Incident Performance and Training Modernization (IPTM) Story Map, a new interactive resource that showcases how NWCG is transforming wildland fire training and qualifications through a performance-based system.

Since its launch in 2023, IPTM has made major strides in updating how we manage incident positions:

  • 36 incident positions now have new Incident Position Standards and Next Generation Position Task Books available for field use
  • 6 more incident positions are nearing completion
  • 111 total incident positions are being analyzed through the IPTM initiative

The Story Map guides you through the IPTM process, highlights key accomplishments, and outlines what’s ahead. Whether you are a trainer or a trainee, this tool offers valuable insight into the modernization effort shaping the future of wildland fire training and qualifications.

This effort would not be possible without the contributions of NWCG staff, NWCG committees, and hundreds of subject matter experts across the wildland fire community.

References:

IPTM Story Map

Incident Performance and Training Modernization Webpage

NEW! S-290, Intermediate Wildland Fire Behavior (Blended) Available Now

Date: Aug 15, 2025
Questions? Please contact:
Fire Behavior Subcommittee

NWCG is excited to announce that the S-290, Intermediate Wildland Fire Behavior (Blended) training is now available on the Wildland Fire Learning Portal. S-290 (Blended) training combines online training and instructor-led training components that support individuals working towards any Single Resource Boss or Fire Effects Monitor incident qualifications.

This second course in the series collectively serves to develop fire behavior prediction knowledge and skills, and provides more detailed information on fuels, weather, and topography that affect wildland fire behavior for safety purposes.

Students are required to finish the prerequisite S-190, Introduction to Wildland Fire Behavior, before enrolling in S-290, Intermediate Wildland Fire Behavior (Blended).

References:

S-290, Intermediate Wildland Fire Behavior (Blended)

S-190, Introduction to Wildland Fire Behavior

Wildland Fire Learning Portal

NEW! S-271, Helicopter Crewmember (Blended) Now Available

Date: Aug 14, 2025
Questions? Please contact:
Interagency Helicopter Operations Subcommittee

The S-271, Helicopter Crewmember (Blended) is now available. Developed through the Incident Performance and Training Modernization (IPTM) effort, this training supports individuals working towards Helicopter Crewmember (HECM) incident qualifications. 

S-271, Helicopter Crewmember (Blended) training combines online training and instructor-led training components. This course is designed to provide students with the knowledge and skills necessary to perform the duties of the HECM position, as described in the NWCG Incident Position Standards for Helicopter Crewmember, PMS 350-22.

Any changes to qualification pathways will take effect with the next update of the NWCG Standards for Wildland Fire Position Qualifications, PMS 310-1, scheduled for January 2026.

References:

S-271, Helicopter Crewmember (Blended)

NWCG Helicopter Crewmember (HECM) Position Page

Wildland Fire Learning Portal