See this story – with photos and audio – from CBC.ca on claims by several farmers near Dawson Creek that nearby natural gas hydraulic fracturing operations are making them sick.

“Wilma Avery says her lungs were damaged when one company flared its
wells and gas plant below her house during a weather inversion in March. ‘My doctor came and looked at me and said, “I think you’ve breathed
some noxious fumes.” I said, “I think I did, too,”‘ Avery said. ‘It’s a yellow pall that was completely around me. I had a cough that
lasted — to put it crudely, you lose all control of everything. Most of
the time I just sat on the toilet and coughed. All I’m asking is this
should never happen again, because the next time it’ll probably kill
me.'”

http://www.cbc.ca/news/canada/british-columbia/story/2011/09/28/bc-shale-gas-sick-farmers.html