UPDATE: Smell in Kenosha Identified, but source Still Unknown
Since the beginning of March, various agencies within the City of Kenosha have been trying to investigate the source of unpleasant vapors coming from the sewer system. A group of leaders in the city met on Monday to assess the results of a sampling of the odor according to a press release from the Kenosha County Sheriff's Department.
On March 12 extensive sampling of the sewer lines in the problem area was conducted by the Kenosha Water Utility in cooperation with We Energies and their consultant, Natural Resource Technology. Briefly, the analysis revealed that the material causing the vapor is “weathered gasoline”. Additionally, sampling from the vacant manufactured gas plant property, which was the original suspected source, was found to be chemically and physically different from the material creating the problem in the sewer line. Therefore, the city has decided that the manufactured gas residue can be ruled out.
Because of the sampling, DNR research indicated that “gasoline” had been detected underground in the problem area some years ago. During pre-road construction borings dating back to 2001, high levels of gasoline had been detected. It is currently unknown if any action was taken from those findings in the past, but according to the release it is very possible that this gasoline has been in the ground for numerous years.
Analysis of the “weathered gasoline” also shows that it is post leaded-gasoline. This indicates it was produced sometime after the mid-1970s.
The exact source of the gasoline is unknown, but current information has led officials to consider past leaking of an underground storage tank. This could have been from an old gas station long since removed, or an old existing underground storage tank unknown to the city.
In the coming days the Kenosha Water Utility will be developing a strategy to systematically clear material from the affected sewer lines. This cannot guarantee the contaminant will not leach back into the sewer. Continued testing and historic property evaluation is planned.
Residents and property owners in the affected area are encouraged to contact the fire department if they notice vapors within their home or basement at 656-1234. If you are immediately concerned the Sheriff's Office says to call 911.