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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.

 

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NWCG Latest Announcements

ETC/RMC Safety Bulletin: 25-001 New Guidance on Laundering Wildland Fire Clothing to Reduce Contamination

Date: Aug 8, 2025
Questions? Please contact:
Equipment Technology Committee
 Risk Management Committee

The Equipment Technology Committee (ETC) and the Risk Management Committee (RMC) have issued Safety Bulletin 25-001: Laundering to Decontaminate Wildland Fire Clothing. Recent research revealed that wildland fire flame-resistant pants and shirts can be contaminated with chemicals from combustion byproducts, including carcinogens, and that common laundering practices can effectively remove these harmful contaminants from wildland firefighter clothing more effectively than previously understood. It is recommended to decontaminate wildland fire clothing as frequently as possible. 

Frequently Asked Questions about this new information and how to implement recommendations can be found on the NWCG Alerts page. Read the complete ETC/RMC Safety Bulletin: 25-001 to learn more. 

References:

NWCG Alerts

ETC Safety Bulletin: 25-001

Frequently Asked Questions (FAQ) on Laundering to Decontaminate Wildland Fire Clothing

Equipment Technology Committee

Risk Management Committee

FAQ Now Available for Archiving Type 1 and Type 2 Incident Positions

Date: Aug 6, 2025
Questions? Please contact:
Incident and Position Standards Committee

To support the transition to Complex Incident Management (CIM), NWCG will archive all Type 1 and Type 2 Command and General Staff (C&G) position qualifications in January 2026, as outlined in NWCG Executive Board Memo 25-002. To assist with this transition, a new Frequently Asked Questions (FAQ) document is now available.

This resource answers common questions about the status of Type 1 and Type 2 qualifications, impacts to incident qualification management, training requirements, and resource ordering considerations. Review the full FAQ to learn more.

For additional information on CIM and the transition of C&G positions, see NWCG Executive Board Memos 23-005, 24-005, and 25-002, as well as the Incident Workforce and Development Group webpage.

References:

NWCG Type 1 & Type 2 Position Archiving FAQ

NWCG Executive Board Correspondence

Incident Workforce Development Group

Incident and Position Standards Committee

Incident Position Standards and the Next Generation Position Task Books Now Available for UASD, UASM, UASL and UASP

Date: July 31, 2025
Questions?  Please contact:
Interagency Fire Unmanned Aircraft Systems Subcommittee
 

NWCG is excited to announce that Incident Position Standards and the Next Generation Position Task Books are now available for all four Unmanned Aircraft Systems positions:

  • Unmanned Aircraft Systems, Data Specialist (UASD)
  • Unmanned Aircraft Systems, Manager (UASM)
  • Unmanned Aircraft Systems, Module Leader (UASL)
  • Unmanned Aircraft Systems Pilot (UASP)

The Performance Support Packages for these positions were developed as part of the Incident Performance and Training Modernization effort. These resources support trainees, qualified personnel, and evaluators in their respective roles.

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:

NWCG Unmanned Aircraft Systems, Data Specialist Position Page

NWCG Unmanned Aircraft Systems, Manager Position Page

NWCG Unmanned Aircraft Systems, Module Leader Position Page

NWCG Unmanned Aircraft Systems Pilot Position Page

Incident Position Standards and the Next Generation Position Task Books Now Available for RADO and INCM

Date: July 30, 2025
Questions?  Please contact:
Incident Logistics Subcommittee
 

NWCG is excited to announce that Incident Position Standards and the Next Generation Position Task Books are now available for Radio Operator (RADO) and Incident Communications Center Manager (INCM).

The Performance Support Packages for these positions were developed as part of the Incident Performance and Training Modernization effort. These resources support trainees, qualified personnel, and evaluators in their respective roles.

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:

NWCG Radio Operator Position Page

NWCG Incident Communications Center Manager Position Page