Definitions

IDLH

Immediately Dangerous to Life or Health — any atmosphere that poses an immediate threat of death, incapacitation, irreversible health effects, or impaired escape. All interior structure fires are presumed IDLH until proven otherwise.

Two-In

The initial interior team of at least two members, operating together with voice or visual contact, on SCBA, with tactical communications to outside personnel.

Two-Out

At least two members outside the IDLH atmosphere, in full PPE with SCBA donned and ready, in direct communication with the interior team, and prepared to effect rescue.

Imminent Life Hazard Exception

OSHA permits initial entry prior to full Two-Out staffing only when there is a known, imminent life hazard and immediate action may prevent death. Requires documentation.

Purpose

To ensure [DEPARTMENT NAME] complies with the respiratory protection standard in every interior attack or search operation conducted in an IDLH atmosphere, and to protect members from operating alone or without prompt rescue capability.

Scope

Applies to every member of [DEPARTMENT NAME] and every interior operation in any IDLH atmosphere: structure fires (offensive or investigation), hazmat operations above the Awareness level, confined-space entries, and any other operation requiring SCBA in an atmosphere that may cause harm.

Policy

1. No member will enter an IDLH atmosphere alone. Minimum interior team size is two members.
2. No interior team will operate in an IDLH atmosphere unless at least two qualified members are stationed outside, fully protected, and prepared to effect rescue.
3. Outside members may be engaged in other duties (e.g., pump operations, hydrant supply) but must be immediately available to respond to a rescue — not engaged in a task they cannot instantly abandon.
4. Interior and exterior members must maintain voice or radio contact at all times.

Imminent Life Hazard Exception

OSHA permits a team of two to enter an IDLH atmosphere before the Two-Out is in place only when a known, imminent life hazard exists and immediate action may prevent loss of life. Use of this exception is documented on every incident where it applies.

• The IC must affirmatively decide to use the exception — it is not invoked by default.
• "Smoke showing" is not sufficient justification. A known occupant — seen, heard, reported by a reliable source, or reasonably expected from the occupancy and time of day — is required.
• Full Two-Out must be established as soon as additional members arrive.
• The exception is documented in the incident report narrative, including the basis for the imminent life hazard, time of entry, and time Two-Out was achieved.

Rescue Responsibility

The Two-Out personnel are the initial rescue crew. They are not the formal Rapid Intervention Team (RIT). RIT is established as a dedicated, additional resource on working fires per the department's RIT SOG. Two-Out personnel may be reassigned to RIT when RIT arrives and is ready to assume the rescue standby role.

Responsibilities

Documentation

Every incident involving interior operations in an IDLH atmosphere is documented in the incident narrative to include: time of entry, composition of interior team, composition of Two-Out standby, use of the Imminent Life Hazard Exception (if any) and its justification, and time the formal RIT was established.

Training Requirements

• All members are trained on Two-In/Two-Out at onboarding and annually thereafter.
• Training includes: recognizing IDLH conditions, verifying compliance before entry, proper use of the Imminent Life Hazard Exception, and transition from Two-Out to formal RIT.
• Training is documented in each member's record.

References

• 29 CFR 1910.134(g)(4)OSHA Respiratory Protection — Procedures for IDLH atmospheres
• OSHA Interpretation LettersFederal OSHA published interpretations of 1910.134(g)(4) for the fire service
• NFPA 1500Standard on Fire Department Occupational Safety, Health, and Wellness Program
• NFPA 1407Standard for Training Fire Service Rapid Intervention Crews

Adapt this template

Before this template becomes your department's policy, review the following items and adjust accordingly. Anything else that does not match your operation should be updated as well.

• If your state has an OSHA State Plan, confirm your state's interpretation — some states have stricter or more detailed requirements.
• If your department routinely uses the Imminent Life Hazard Exception, create a standard incident narrative template so documentation is consistent.
• Cross-reference this SOP to your department's Incident Command, RIT, and SCBA procedures.