Date Published

April 8, 2014

Updated For

ALS PCS Version ALS PCS Version 5.2


Question: I am seeking direction in the management of a patient(s) who have sustained exposure to Hydrogen Sulfide (H2S) in suicide; taking into account the presenting HAZ-Mat situation and the associated dangers to 911 allied agency personnel. Specifically, assessments, resuscitation, TOR, field pronouncement, transport guidelines and recommendations.

My major concern is the potential harm to transporting crews due to external ventilation of the lethal gases notably if the Fire Dep't "4 Gas Monitor" monitors indicate a presence of H2S.


 Great question, and certainly the risk of H2S is real to all Emergency Responders. The first consideration should be responder safety. If there is any concern for the presence of any hazardous material at a scene, you and your partner should remain at a safe distance and await fire or fire hazmat to clear the scene or extract the patient. If their meters are registering H2S than appropriate decontamination must occur prior to patient contact and assessment.

H2S is a gas and is not persistent, therefore, once the patient has been appropriately decontaminated they are no longer a risk to you or any other first responders. There has been some question as how much H2S may remain in the lungs of these patients after exposure. This was discussed with toxicology/hazmat physicians and it is felt that if the patient is spontaneously breathing, there will be none left by the time patient contact is made. If the patient is not breathing, there is the possibility that some H2S remains as a result of the Functional Residual Capacity of the patients lungs. After the first few BVM ventilations this will be washed out but it is recommended that this should be done in a well ventilated area.

Resuscitation should follow the current protocols, taking into consideration that an arrest following H2S exposure would qualify as a special circumstance and should be considered for early transport as an antidote is available in some Emergency Departments. There is a podcast style webinar on our website reviewing H2S from both a EMS and fire perspective that reviews all of these topics in more detail:



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