Last year in Michigan they thought that the demolition of the gas plant was the end of that odorous nuisance, but Sulfolane (used to purify sour gas) was left behind in the soil & groundwater on the site.
Per http://www.ernstversusencana.ca/nikiforuk-whats-missing-from-canadas-academic-fracking-debate-the-gritty-truth “… an acid injection site in Edson, Alberta is likely involved in the widespread contamination of drinking water wells with sulfolane, …”
This recent report at Ridgelinecanada.com shows that oil & gas companies in Alberta are getting notices to report on Sulfolane use and how to look for its insidious contamination.
Per Ridgeline, “Sulfolane is a persistent contaminant in groundwater and is presumed not to breakdown easily in low oxygen/low nutrient environments. Sulfolane moves with groundwater and because it is slightly heavier than water it will migrate downwards, often to bedrock”.
Natural gas just leeps getting nastier by the knowing.