Potential Hydrogen Sulfide (H2S) concern at Piedmont Lake

Published Sept. 9, 2020

HUNTINGTON, W.Va. - The Huntington District of the U.S. Army Corps of Engineers has determined that conditions exist in the outlet works area at Piedmont Lake in Piedmont, Ohio, that could result in the presence and possible release of hydrogen sulfide (H2S) gases.

Hydrogen sulfide is a colorless gas that can be easily recognized by its “rotten egg” odor. Symptoms of exposure vary depending on the level and duration of exposure.  Low concentrations irritate the eyes, nose, throat and respiratory system. Asthmatics may experience breathing difficulties. Exposure to moderate concentrations can also cause fatigue, dizziness, nausea and headaches. Young children are at particular risk.

This problem is normally confined to the area adjacent to the outlet works and is not known to pose a problem to recreational users of the lakes. There is no indication that fish taken from these lakes pose a health risk if consumed.

The Corps will monitor H2S levels at the outlet works. Project employees will take readings to detect any presence of H2S gases around the outlet works and surrounding areas.  

In the event that H2S gases at any public access site in these areas reaches levels that could pose a health risk to the public, those areas will be closed. Due to public safety, the area immediately adjacent to the discharge at Piedmont Lake has been closed and will remain closed until the problem naturally corrects itself.

Hydrogen sulfide forms when the concentrations of sulfates in the watershed immediately behind these dams are higher than normal. During the summer months, the sulfates are converted to hydrogen sulfide gas through microbial activity occurring in the bottom layers of the lake. As the water leaves the lake, the hydrogen sulfide gas is released into the air, creating an unhealthy situation in the tailwater areas. 

Corps personnel will continue to monitor the situation for the presence of H2S and will notify appropriate agencies as well as the public if H2S concentration levels are determined to pose a threat to public safety.    

For more information, please contact the Muskingum Area Office at 330-365-4255 or the Public Affairs Office at 304-399-5353.


Muskingum Area Office
Public Affairs Office

Release no. 20-041