Hydrogen Sulfide (H(2)(S)) CAS: 7783-06-4; UN 1053
Synonyms of hydrogen sulfide include dihydrogen sulfide, sulfur hydride, sulfuretted hydrogen, "sewer gas, " and "stink damp."
- Hydrogen sulfide is a highly flammable and explosive gas produced naturally by decaying organic matter and by certain industrial processes.
- Hydrogen sulfide has a characteristic rotten-egg odor; however, olfactory nerve paralysis may occur, which makes odor an unreliable warning property.
Description --
Hydrogen sulfide is a colorless, flammable, highly toxic gas. It is shipped as a liquefied, compressed gas. It has a characteristic rotten egg odor that is detectable at concentrations as low as 0.0 2 ppm.
Routes of Exposure --
Inhalation -
Inhalation is the major route of hydrogen sulfide exposure. The gas is absorbed rapidly by the lungs. Although its strong odor is readily identified, olfactory nerve paralysis occurs at persistent low concentrations and at high concentrations. For this reason, odor is not a reliable indicator of hydrogen sulfide's presence and may not provide adequate warning of dangerous concentrations. Hydrogen sulfide is slightly heavier than air and may accumulate in enclosed, poorly ventilated, and low-lying areas.
Skin/Eye Contact -
Prolonged exposure to hydrogen sulfide, even at relatively low levels, may result in painful dermatitis and burning eyes. Direct contact with the liquefied gas can cause burns and frostbite. Absorption through intact skin is minimal.
Ingestion -
Since hydrogen sulfide is a gas at room temperature, ingestion is unlikely to occur.
Sources/Uses -
Hydrogen sulfide is produced naturally by decaying organic matter and is released from sewage sludge, liquid manure, sulfur hot springs, and natural gas. It is a byproduct of many industrial processes including petroleum refining, tanning, mining, wood pulp processing, rayon manufacturing, sugar beet processing, and hot asphalt paving. Hydrogen sulfide is used to produce elemental sulfur, sulfuric acid, and heavy water for nuclear reactors.
Properties of Hydrogen Sulfide -
Appearance: Colorless gas with odor of rotten eggs
Warning properties: Undependable; characteristic rotten-egg odor detectable at about 0.02 ppm, but olfactory nerve paralysis occurs in 2 to 15 minutes at 100 to 150 ppm
OSHA PEL (Permissible Exposure Limit) = 10 ppm (averaged over an 8-hour workshift)
OSHA STEL (Short Term Exposure Limit ) = 15 ppm (15-minute sample)
NIOSH IDLH (Immediately Dangerous to Life or Health) = 300 ppm
AIHA ERPG-2 = 30 ppm
Molecular weight = 34.1
Boiling point (760 mm Hg) = -77 F (-60.6 (7)
Vapor pressure (67 F) = > 760 mm Hg
Vapor density = 1.2 (air = 1 )
Slightly water soluble (0.4% at 20 C)
Highly flammable and explosive between 4% and 44% (concentration in air); may travel to a source of ignition and flash back
Health Effects
- Hydrogen sulfide can be rapidly fatal. It can paralyze the respiratory control center in the brain and inhibit cellular respiration.
- Hydrogen sulfide is a mucous membrane and respiratory tract irritant; pulmonary edema, which may be immediate or delayed, can occur alter exposure to high concentrations.
Acute Exposure --
Acute Exposure Hydrogen sulfide's mechanism of toxicity is similar to that of cyanide inhibition of the cytochrome oxidase system resulting in cellular asphyxia. Metabolic acidosis can occur secondary to anaerobic metabolism. Hydrogen sulfide is also a mucous membrane and respiratory tract irritant.
Nervous system -
Upon exposure to hydrogen sulfide, the central nervous system suffers the most immediate and significant insult. At high concentrations, only a few breaths can lead to loss of consciousness, respiratory paralysis, seizures, and death. CNS stimulation may precede significant depression. Stimulation manifests as excitation, tachypnea, and headache; depression manifests as staggering gait, dizziness, and unconsciousness, possibly progressing to respiratory paralysis and death. In addition, olfactory nerve paralysis occurs at 100 to 150 ppm.
Respiratory -
Inhaled hydrogen sulfide affects initially the nasopharynx. Low concentrations (< 50 ppm) can produce rapid irritation of the nose, throat, and lower respiratory tract. Pulmonary manifestations include cough, dyspnea, and hemoptysis. Higher concentrations can provoke bronchitis and pulmonary edema, which may be immediate or delayed for 24 hours or more. Hypoxia may result in cyanosis.
Cardiovascular -
High-dose exposures may cause myocardial depression, dysrhythmias, and conduction abnormalities.
Renal -
Transient renal effects include hematuria, cylindruria, and proteinuria. Renal failure as a direct toxic effect of hydrogen sulfide has not been described, although it can occur secondary to cardiovascular compromise.
Gastrointestinal -
Symptoms may include nausea and vomiting.
Ocular-
Irritation may cause keratoconjunctivitis and corneal opacity. Symptoms include blurting of vision, photophobia, and blepharospasm.
Dermal -
Potential Sequelae Prolonged or massive exposure may cause burning, itching , erythema, and painful dermatitis.
Potential Sequelae -
Bronchopneumonia can be a late development. Survivors of severe exposure may suffer psychic disturbances and permanent damage to the brain and heart.
Chronic Exposure --
Hydrogen sulfide does not accumulate in the body. Nevertheless, repeated or prolonged exposure has been reported-to cause hypotension, headache, nausea, loss of appetite, weight loss, impaired gait, conjunctivitis, and chronic cough. Neurologic symptoms including psychological disorders have been associated with chronic exposure.
No studies on the possible carcinogenic activity of hydrogen sulfide were found.
Reports in which human reproductive and developmental effects were noted involved mixed exposures. Hydrogen sulfide is not listed in TERIS or in Shepard's Catalog of Teratogenic Agents. It also is not included in a 199 1 report published by the U.S. General Accounting Office, which lists 30 chemicals of concern because of their reproductive and developmental consequences. In the absence of maternal toxicity, reproductive and developmental consequences appear unlikely to occur.
Prehospital Management
- Hydrogen sulfide is a highly toxic gas that can produce respiratory irritation, rapid CNS and respiratory depression.
- There are no proven antidotes for hydrogen sulfide poisoning. Treatment requires aggressive supportive measures.
Potential for Secondary Contamination --
Victims exposed to only hydrogen sulfide gas do not pose a significant risk of secondary contamination to personnel outside the Hot Zone.
Hot Zone --
Rescuers should be trained and appropriately attired before entering the Hot Zone. If the proper equipment is not available, or if rescuers have not been trained to use it, call for assistance from a local or regional hazmat team or other properly equipped response organization.
Rescuer Protection -
Rescuers in the Hot Zone should wear self-contained breathing apparatus (SCBA). Chemical-protective clothing and gloves is not required for brief entry for victim rescue. If prolonged exposure in the Hot Zone is anticipated, chemical-protective clothing is recommended to prevent dermatitis.
ABCs -
Quickly establish a patent airway. Stabilize the cervical spine with a collar if trauma is suspected. Administer supplemental oxygen and assist ventilation with a bag-valve-mask device if necessary.
Victim Removal -
If victims can walk, lead them out of the Hot Zone to the Decontamination Zone Ira victim is unable to walk, remove him or her on a backboard or gurney. If there is no means of transport, carefully drag the victim out.
Decontamination Zone --
Victims with exposure to only hydrogen sulfide gas and with no skin or eye irritation do not need decontamination. They may be transferred immediately to the Support Zone. For all others, see Basic Decontamination.
Rescuer Protection -
Rescuers in the decontamination zone require no specialized protective gear since patients exposed to hydrogen sulfide gas pose no serous risk of causing secondary contamination.
ABCs -
Quickly establish a patent airway. Stabilize the cervical spine with a collar if traumas suspected. Supplemental oxygen can be administered if available. Evaluate the need for an intravenous line, cardiac monitor, and life support.
Basic Decontamination -
Remove and double-bag contaminated clothing. Patients who axe able and cooperative may remove their own clothing and assist with basic decontamination.
Flush exposed skin and hair with plain water for 2 to 3 minutes. Flush exposed or irritated eyes with plain water or saline for 3 to 5 minutes. Remove contact lenses if present.
Patient Transfer -
As soon as basic decontamination is completed, move the patient to the Support Zone.
Support Zone --
Be certain that patients have undergone basic decontamination (see Decontamination Zone above). Patients who have undergone proper decontamination or who have been exposed to only vapor pose no serious risk of causing secondary contamination. Support Zone personnel require no specialized protective gear in such cases.
ABCs -
Quickly establish a patent airway. Stabilize the cervical spine with a collar if trauma is suspected. Administer supplemental oxygen and assist ventilation with a bag-valve-mask device if necessary. Evaluate the need for an intravenous line, cardiac monitor, and life support.
Advanced Treatment -
Intubate the trachea if indicated (severe respiratory compromise or apnea). When endotracheal intubation cannot be performed due to airway obstruction, perform cricothyroidotomy if equipped and trained to do so. Treat wheezing and bronchospasm with aerosolized bronchodilators.
Additional Decontamination -
If skin or eyes remain irritated, flush with plain water or saline for 3 to 5 minutes. Remove contact lenses if present.
Transport to Medical Facility -
Report to the base station and receiving medical facility the condition of the patient, treatment given, and estimated time of arrival at the medical facility.
Multi-Casualty Triage --
If possible, consult with the base station physician or regional poison control center for advice regarding triage of multiple victims.
All patients with potentially significant exposure should be evaluated at a medical facility.
Currently asymptomatic patients with a history transient eye, nose, or throat irritation or dizziness or nausea may be released from the scene after recording their names, addresses, and telephone numbers. They should be encouraged to rest and to seek medical care if symptoms of toxicity develop.
Emergency Department Management
- Hydrogen sulfide is a highly toxic gas that can produce respiratory irritation, rapid CNS and respiratory depression.
- There are no proven antidotes for hydrogen sulfide poisoning. Treatment requires aggressive supportive measures.
Potential for Secondary Contamination --
Hospital personnel away from the scene are at little risk of secondary contamination from patients exposed to only hydrogen sulfide gas; however, personnel can be secondarily contaminated by contacting or breathing vapors from clothing heavily soaked with hydrogen sulfide-containing solution.
Decontamination Area --
Patients with exposure to only hydrogen sulfide gas and with no skin or eye irritation do not need decontamination. They can be transferred immediately to the Critical Care Area. Other patients will require decontamination as described below.
ABCs -
Evaluate and support airway, breathing, and circulation. Monitor cardiac rhythm.
Basic Decontamination -
If the patient has not been decontaminated, perform the decontamination procedure immediately. Remove and double-bag the contaminated clothing and all personal belongings. Flush the exposed skin with copious water (preferably under a shower).
Remove contact lenses and irrigate exposed eyes with water for at least 15 to 30 minutes. An ophthalmic anesthetic, such as 0.5% tetracaine, may be necessary to alleviate blepharospasm, and lid retractors may be required to allow adequate irrigation under the eyelids.
Critical Care Area --
Be certain that appropriate decontamination has been carried out. See Decontamination area.
ABCs -
Evaluate and support airway, breathing, and circulation. Continuously monitor cardiac rhythm.
Assess and treat hypotension and seizures in the conventional manner. Patients with significant and persistent CNS depression should be evaluated
for the presence of intercurrent disorders (e.g., trauma, hypoglycemia, and drug intoxication).
Inhalation Exposure -
Administer supplemental oxygen by mask to patients with respiratory complaints and observe them for 24 hours using repeated chest examinations and other appropriate tests. Follow-up as clinically indicated.
Skin Exposure -
If concentrated hydrogen peroxide solution was in contact with the skin, chemical bums may result. Treat chemical bums as thermal bums.
Eye Exposure -
If eye irritation or injury is evident, test visual acuity and examine the eyes for corneal damage using a magnifying device or a slit lamp and fluorescein staining. Small corneal defects may be treated with topical ophthalmic antibiotic ointment or drops and analgesic medication. Immediately consult an ophthalmologist for patients with severe corneal injury.
Antidotes and Other Treatments -
Theoretically, administration of nitrites to produce methemoglobinemia may promote conversion of systemic sulfide ion to sulfhemoglobin, which is far less toxic. However, there is only anecdotal evidence that nitrite therapy is effective and victims of hydrogen sulfide poisoning have survived without sequelae after supportive care alone. Furthermore, the usefulness of nitrite therapy given late in the course of management (beyond the first few minutes after exposure) is questionable. For adults, the reported dose is 10 to 15 mL of an IV solution of 3% sodium nitrite infused over at least 5 minutes. For children, the reported dose is O. 15 to 0.2 mL/kg, not to exceed 10 mL, infused over at least 5 minutes.
Hyperbaric oxygen therapy is controversial and based on anecdotal evidence. It may be efficacious in patients in whom other treatments were unsuccessful.
Laboratory Tests -
Useful laboratory studies include CBC, electrolytes, glucose, renal function tests, and liver function tests. Arterial blood gases and chest radiography may be helpful in cases of inhalation exposure.
Disposition and Follow-up --
Delayed Effects -
Patients who suffer unconsciousness or hypotension should be observed closely for complications including post hypoxic encephalopathy. Because pulmonary edema may be delayed, seriously exposed patients with inhalation exposure should be monitored for 24 hours. If pulmonary edema is suspected, admit patients to an intensive care unit.
Patient Release -
Asymptomatic patients with no evidence of pulmonary edema or CNS or respiratory compromise and with no signs of eye irritation, may be discharged after 4 to 6 hours of observation. These patients should be instructed to return to the ED if symptoms of toxicity develop.
Follow-up -
Patients exposed to hydrogen sulfide should be monitored for possible damage to the heart and brain, including evaluation for neurologic deficits.
Reporting --
If a work-related incident has occurred, you may be legally required to file a report; contact your state or local health department.
Other persons may still be at risk in the setting where this incident occurred. OSHA may be contacted for assistance in evaluating workplace conditions, or an appropriate public agency can be notified if a public health risk exists. If appropriate, inform patients that they may request an evaluation of their workplace from the Hazard Evaluation Division at NIOSH.
Hydrogen Sulfide Patient Information Sheet
This handout provides information and follow-up instructions for persons who may have been exposed to hydrogen sulfide.
What is hydrogen sulfide?
Hydrogen sulfide is a highly toxic, colorless gas with a rotten-egg odor. It is produced naturally by decaying organic matter and is released from sewage sludge, liquid manure, sulfur hot springs, and natural gas. It is used in several industries and is a by-product of many industrial processes such as oil refining, mining, and rayon manufacturing.
What immediate health effects may result from hydrogen sulfide exposure? Hydrogen sulfide has a strong rotten-egg odor even at low concentrations. However, with continued exposure and at high levels, the poison may deaden a person's sense of smell, making the individual unaware that he or she continues to be exposed to hydrogen sulfide. If the rotten egg odor is no longer noticeable, it may not necessarily mean that exposure has stopped. After a serious exposure, symptoms usually begin immediately. At low levels, hydrogen sulfide causes irritation of the eyes, nose, and throat. Moderate levels can cause headache, dizziness, nausea, and vomiting, as well as cough and breathing difficulty. Higher levels can cause shock, convulsions, coma, and death.
What is the treatment for hydrogen sulfide poisoning?
The main treatment is to remove the victim from exposure and give fresh air and oxygen, and to take the person to an emergency medical facility for evaluation. There is no proven specific antidote for hydrogen sulfide poisoning.
Are any future health effects likely to occur?
After a single, small exposure with quick recovery, no delayed or long term effects are likely to occur. After a serious exposure that causes coma or convulsions, damage may have been done to the brain and heart.
What tests can be done if a person has been exposed to hydrogen sulfide? Specific tests for the presence of hydrogen sulfide in blood and urine are not medically useful. If a severe exposure has occurred, blood, urine, and other tests may show if damage has been done to the brain, nerves, heart, kidneys, or liver. If hydrogen sulfide was inhaled, blood tests and a chest X ray may be necessary to determine if the lungs have been injured. Testing is not needed in every case. Generally, the severity of symptoms is the best measure of the seriousness of the exposure.
Where can more information about hydrogen sulfide be found? More information about hydrogen sulfide may be obtained from your regional poison control center; your state, county, or local health department; the Agency for Toxic Substances and Disease Registry (ATSDR); your doctor; or a clinic in your area that specializes in occupational and environmental health. If the exposure happened at work, you may wish to contact the Occupational Safety and Health Administration (OSHA) or the National Institute for Occupational Safety and Health (NIOSH). Ask the doctor who gave you this form for help in locating these telephone numbers.
Hydrogen Sulfide Follow-up Instructions
( ) Call your doctor or the Emergency Department if you develop any of the
following symptoms within the next 24 hours:
* cough, wheezing, difficulty breathing or shortness of breath
* chest pain
* increased redness, pain, or pus-like discharge in the area of a skin
* headache
* memory loss or personality changes
* belly pain, vomiting, diarrhea
( ) No follow-up appointment is necessary unless you develop any of the
symptoms described above.
( ) Call for an appointment with Dr. _________ in the practice of_________.
When you call for your appointment, please tell the receptionist/nurse that
you were treated in the Emergency Department at__________________ Hospital by
__________ and were advised to be seen again in __ days.
( ) Return to the Emergency Department/__________Clinic on (date)__________
at____ AM/PM for a follow-up examination.
( ) Do not perform vigorous physical activities for __ days.
( ) You may resume everyday activities including driving and operating
machinery.
( ) Do not return to work for __ days.
( ) You may return to work on a limited basis. See instructions below.
( ) Avoid exposure to cigarette smoke for 24 hours since smoke may worsen
injury to your lungs.
( ) Avoid drinking alcoholic beverages or taking aspirin for 24 hours since
these substances may aggravate injury to your stomach lining or may have
other effects.
( ) You may continue taking the following medication(s) that your doctor(s)
prescribed for you:____________________________________________________
_______________________________________________________________________
( ) Other instructions:____________________________________________________
_______________________________________________________________________
Signature of patient _______________________ Date _________________________
Signature of physician _____________________ Date _________________________
Above courtesy of C.D.C.
