An investigation into the blowout of a well near Innisfail last January shows fracking was responsible.

The blowout spewed nearly 500 barrels of oil and water onto a central Alberta field, affecting 4.5 hectares and requiring the removal of just over 1,000 tonnes of soil and snow.

The Energy Resources Conservation Board released the results of its investigation on Wednesday.

The board found Midway Energy didn't follow its own guidelines — which says its drill hole should have been at least 135 metres from any other well — when it began pumping high-pressure fluids underground in an attempt to release oil deposits.

"Midway did not conduct the fracturing operation in compliance with its own internal procedures," concluded the board's investigation.

The result was a geyser of oil, natural gas, process water and fracking fluids from an adjacent well owned by Wild Stream Exploration, which has since been sold and now operates as Raging River Exploration.

The mixture tainted the field and left a thin film on nearby trees, but the board concluded ground water wasn't affected.

The board found both wells were targeting the same formation about 1,800 metres underground.

"The company essentially drilled too close to another well bore, so it's really an unusual circumstance where we'd have this type of blowout. So yes, it is bad judgment," said ERCB spokesman Darin Barter.

At the time, there were no provincial guidelines to indicate where it was safe for a company to frack.

Barter said no penalties will be handed down because the blowout didn't contravene any regulations.

But as a result of the Midway blowout, Barter said the ERCB has drafted guidelines for fracking in the area that will come into effect in the coming months.

Midway Energy has since been bought out by Whitecap Resources.

With files from The Canadian Press