Gas found in Versailles could be more dangerous than thought
The U.S. Environmental Protection Agency is considering broadly regulating hydrogen sulfide, a common gas that smells like rotten eggs and has been increasingly linked to a variety of health problems for people living and working near petroleum, confined livestock, paper and landfill operations.
The gas was found in Versailles last year by the U.S. Department of Energy. In one location, the gas was detected at a concentration considered dangerous, but follow up testing by the Allegheny County Health Department and the Pennsylvania Department of Health found only low levels and officials said those levels were not a health concern.
Hydrogen sulfide has long been known to be deadly in high concentrations. However, growing scientific evidence shows the gas may also have health effects at low levels.
The agency is "reviewing existing scientific information to determine whether a listing is justified, and we are conducting our own studies in order to fill data gaps -- so that ultimately, we will be able to make a determination," Alison Davis, a spokeswoman for the EPA's Office of Air Quality Planning and Standards, said in an email statement.
In a report about the hydrogen sulfide found in Versailles, the Department of Energy said the gas was likely coming from the decay of organic materials in an abandoned natural gas well. A device to remove the gas was installed in the well.
Versailles has problems with hundreds of abandoned natural gas wells drilled around 1920, which are now leaking methane, which is not as harmful as hydrogen sulfide. The borough -- which declared a state of emergency after a leaking well was found in August -- is considering plans to properly vent the wells.
Hydrogen sulfide is produced when organic material containing sulfur decomposes, such as in sewage. It can also be produced from chemical reactions. The gas is readily found in the Earth's crust and in extremely low levels in the atmosphere. In dumps specializing in construction and demolition debris it can be produced when gypsum, the main ingredient in wallboard, decomposes.
The gas was once thought to be relatively harmless in low concentrations. Some scientists and federal health investigators say mounting research in recent years shows that prolonged exposure to relatively low levels may affect memory, coordination, eyes and breathing. Among them, a study published in 2002 by a University of California-Berkeley scientist and others suggest New Zealand residents of Rotorua living near hot springs, geysers and other geothermal sources of hydrogen sulfide had increased risk of nervous system, lung and eye problems.
However, those researchers caution that more study is needed, and note that communities studied are often exposed to several chemical compounds at the same time, clouding the results.