Sour gas flare in Louisiana's Barataria Bay.Shortly before Hurricane Katrina’s winds and waters inundated Mississippi’s coast, the Mississippi Development Authority (MDA) had pushed to open Mississippi waters to natural gas drilling and production. Though the prospect was rebuffed by widespread public opposition from Mississippi residents and citizen groups like the 12 Miles South Coalition, this threat to the health of Mississippi’s coast resurfaced this past December. MDA issued draft rules that would regulate any seismic testing or mineral leasing in State waters. The final rules were published in February of this year, but are currently on hold due to the lawsuit filed by Gulf Restoration Network and Sierra Club. You may be familiar with many of the arguments against offshore oil and gas drilling along Mississippi’s coast—i.e. the impacts on tourism, the heightened risk of pollution, or the potential harm to coastal barrier islands. Resistance to drilling and production however also includes a seldom-discussed yet serious issue: the release of hydrogen sulfide gas.
Hydrogen sulfide (H2S) is a naturally occurring component of natural gas. Commonly referred to as “sour gas,” H2S can be emitted routinely or accidentally during the oil and gas extraction process. Because H2S cannot be sold, it is usually flared (or burned) as a safety measure. The combustion of H2S results in the release of sulfur dioxide (SO2), but in the event of incomplete combustion, H2S can also be released into the atmosphere. Releases also occur when the flare intended to burn the H2S goes out, and instead H2S is vented directly into the air. The risk of H2S emissions is an issue worth discussing because according to the EPA and other credible sources, H2S poses a significant health risk. In serious instances exposure to H2S is life threatening, but even occupational or accidental exposure can be harmful. For example, the inhalation of H2S in low concentrations can cause migraines, eye and skin irritation, nausea, and respiratory infection. EPA has also found that due to its toxicity, H2S can also cause significant adverse effects in aquatic life.
Natural gas production platforms off the coast of Dauphin Island. The two on the left are approximately 1.4 miles from the coast. Photo courtesy of Dr. Olivia Graves.The potential effects of offshore gas drilling and production in Mississippi waters have occasionally been compared to those on Dauphin Island, AL. A total of five platforms extracting natural gas surround Dauphin Island, a small barrier island in Mobile Bay. In addition to the platforms’ aesthetic effect on Dauphin Island residents and visitors, the potential risk of a hydrogen sulfide release has become a reality. In fact, in 2007 ExxonMobil was responsible for an accidental release of 843 lbs. of H2S from their Mary Ann Field platform in Mobile Bay. Prior to this release, the community of Dauphin Island was not aware that such a danger existed. A local newspaper article describes the hydrogen sulfide emergency that day—the entire island was affected by the sour H2S odor, dozens fell ill, and some were even taken to the doctor or emergency room.
While its stench of rotten eggs is an obvious indicator, H2S rapidly desensitizes our sense of smell and other senses. Communities like those on Dauphin Island have thus invested in H2S monitors and mechanical detectors. Emergency and Rescue departments on Dauphin Island implemented H2S operational guidelines with procedures for detecting, reporting, and responding to hydrogen sulfide emergencies. According to Dauphin Island Mayor Jeff Collier, H2S is a “major issue” for the community. Early notification is essential, yet unfortunately the system for dealing with H2S “isn’t that great yet.” Collier said that while residents and schools know (and even practice) the procedure in the event of an H2S emergency, they have also started posting bulletins in rental properties to warn and notify visitors of what to do in the event of a H2S release.
Sour gas flare in Louisiana's Barataria Bay.Part of the H2S emergency procedure on Dauphin Island includes getting inside as fast as possible, closing the windows and doors, and shutting off any air-conditioning units. Even if a similar procedure is put in place in Mississippi, how would this be achieved on a beach full of people enjoying a day on Ship Island? A charter boat full of visitors to the coast? If the release is severe enough to travel onshore, how fast can people get inside before inhaling a considerable amount of H2S? Dauphin Island has arguably adjusted to the landscape since offshore drilling was first brought there over thirty years ago. Nevertheless, the community is still at the mercy of the gas industry to keep them informed and safe.
Earlier in my post I mentioned how SO2 is the product of burning and removing H2S from natural gas. SO2 emissions are regulated to a much greater degree than H2S (not to mention they’ve received a considerable amount of attention due to their feared ability to produce acid rain.) “Unplanned” releases of sour gas—natural gas containing significant amounts of H2S—are “incidents” and must be reported to the Alabama Department of Environmental Management (ADEM). Most incident reports are triggered from the burning of sour gas longer for longer than 30 minutes or from burning more than 50 lbs. because this produces considerable amounts of SO2. In fact, some incident reports are filed because the facility has breached its allotted quantity of SO2 emissions for the month. In 2010—one of their “dirtiest” years—the Exxon Bon Secour Bay Platform reported over 180 of these incidents. At the Exxon Northwest Gulf Platform, 2009 was one of their dirtiest years, reporting 177 incidents or unplanned releases. While the total quantity of SO2 released can be calculated from these reports, there is no measure of the total H2S released. Furthermore, though under the Emergency Planning and Community Right-to-Know-Act (EPCRA) platforms must report releases of “emergency” classified quantities of H2S, natural gas extraction facilities are exempt from other EPCRA requirements, such as gathering and reporting summarized data on the total amount of H2S released annually. This puzzling fact was confirmed by Kirk Chandler of the Alabama Emergency Response Commission.
H2S releases are one of the many reasons to object to natural gas drilling off the Mississippi Coast, especially given the lack of transparency about how much H2S offshore natural gas production facilities actually release on a regular basis. To learn more about the potential impacts of oil and gas drilling in Mississippi, join Gulf Restoration and the 12 Miles South Coalition this Thursday evening for Oil and Gas in Mississippi’s Waters: A Public Forum.
Whitney Suzanne Whitson is a Legal Intern with GRN.