May 17, 2016

Experts Warn of Hydrogen Sulfide Dangers

Reporting Texas

Hydrogen sulfide, or H2S, is a colorless gas that smells like rotten eggs, but there the similarity ends. At lower levels, the gas causes nausea, headaches and dizziness. Larger doses can result in loss of smell and ultimately death.

The poisonous gas made headlines on April 13 after Austin firefighters responded to a cardiac arrest call in a West Campus apartment building. After searching the building, officials located an apartment with a note on the door reading “Stay out: Hydrogen Sulfide.”

Austin police believe 20-year-old Richard Thanh Truong, an electrical engineering major from Sugarland, took the gas into the apartment in a container and then ended his life by inhaling it, although the Travis County Medical Examiner’s Office is still working on a toxicology report. The Austin American-Statesman reported that the H2S is thought to have traveled through the building’s ventilation system into adjacent areas before emergency responders could evacuate the residents. Eleven people suffered gas inhalation, and six of them were treated for non-life-threatening injuries at University Medical Center Brackenridge.

Battalion Chief Matt Cox of the Austin Fire Department said he has handled several cases involving hydrogen sulfide during his 18 years on the Special Operations team but that they are “very infrequent.” The department has responded to five incidents of the gas within the past 10 years, according to the fire department.

Cox urges anyone smelling an rotten-egg-like odor not to linger in the vicinity. “You can go down the halls and knock on doors and say ‘Hey I’m calling 911,’ but the most important thing is to get out” as quickly as you can, Cox said.

According to Richard Corsi, however, smelling the gas can actually be a good thing. “If you can smell it,” said Corsi, a UT-Austin engineering professor who specializes in the effect of toxins on air quality, it means H2S is “not at levels yet that can harm you.”

Cross said the problem comes when “you can smell it and … you stop smelling it or if you never smell it. That’s when it can be very dangerous.” At certain levels, the gas deadens the trigeminal nerve which transfers sensations from the nose to the brain. Once odorless, the gas becomes especially lethal.

Hydrogen sulfide can form both naturally and artificially. Either way, said Corsi, it “binds with iron in our blood,” which prevents the blood from absorbing the oxygen that keeps cells alive throughout the body. According to the U.S. Centers for Disease Control and Prevention, there were 30 deaths due to hydrogen sulfide nationwide in 2014, including both suicides and industrial accidents.

The U.S. Bureau of Labor Statistics reported 10 fatal occupational incidents involving hydrogen sulfide in 2014, including four in Texas.

The gas is heavier than air, so it poses a particular threat in areas with poor ventilation. With little room to disperse, H2S can become concentrated and dangerous.

Hydrogen sulfide can form naturally in swamps and stagnant ponds with very low oxygen levels. These areas, known as anaerobic environments, are breeding grounds for bacteria that turn sulfur found in organic materials into hydrogen sulfide.

The sulfur can also come from fecal matter in sewers, causing problems for municipal workers. Pipes that are not used frequently can form hydrogen sulfide, and at “high levels of sulfide they can kill you very fast or knock you out very quickly,” Corsi said.

He has experienced the effects of hydrogen sulfide first hand. As an undergraduate student at Humboldt State University in the 1980s, Corsi worked in the desulfurization unit at an oil refinery in Bakersfield, California, where his job was to open a valve releasing hydrogen sulfide buildup from oil stored underground.

“I cracked a valve when I could see the wind was blowing away from me,” Corsi said. “I wasn’t wearing any respiratory equipment at all. [It] turned out the wind at ground level was different from the wind above me, and so it blew the hydrogen sulfide right into my face and knocked me out.”

Incidents involving artificially made gas, as in the case of suicide deaths, are more frequent, Corsi said. Chemical suicides are often attempted in enclosed cars, closets or enclosed areas, making them dangerous for anyone who is sharing the air nearby.

Cox believes that the public has little to worry about from accidental deaths involving H2S because such incidents are relatively rare.

According to the Centers for Disease Control and Prevention, the number of intentional self-poisoning suicides by exposure to gas and vapors in 2014 were 1,131, a decrease from the 1,535 in 1999. Suicides caused by gases or vapors are a small percentage of all suicides:, in 2014, this type of suicide made up almost 3 percent of all reported suicides, a decrease of nearly 2 percentage points from the slightly more than 5 percent in 1999, according to the CDC.

Merily Keller, suicide prevention coordinator in the Austin office of Mental Health America of Texas, said warning signs include hopelessness, consistently declining invitations to events, loss of pleasure in enjoyable  hobbies, sleeping too much or too little and an inability to concentrate.

Keller said the best thing people can do for someone contemplating suicide is to ask directly if the individual is thinking about ending his or her life and then take the reply seriously. Most important, friends can help potential suicides by encouraging them to call Austin Travis County Integral Care or, for UT students, the UT Counseling for Mental Health Center.

Experts on hydrogen sulfide gas and its effects agree on one thing: Whether you confront H2S in a natural setting or in the confines of a building, when you smell that telltale rotten-egg odor, evacuate the area as quickly and safely as possible.