Sometimes hydraulic fracturing of underground shale formations to produce oil and gas goes awry. Pumping fluids into formations at high pressure to release hydrocarbons can cause oil, gas, and toxic liquids to spew from old abandoned wells.
"The hiss of gas escaping was the first indication something was wrong in an oil field near the town of Drayton Valley, an hour as the crow flies from Edmonton, Alberta.
A landowner whose cows graze there in springtime came across the well spewing oil and gas one evening in September 2011. The wind, blowing at about 2 miles per hour, fanned crude oil and chemicals onto the surrounding hay fields.
The landowner telephoned Patrick Sheve, the field operator of Sword Energy Inc. (currently called Journey Energy Inc.), which partly owned the gas well. Sheve hurriedly cut off the power remotely and informed his bosses."