Robert Redford has recorded a series of radio advertisements condemning the controversial process of hydrofracking.

The Oscar winner and environmental activist has loaned his voice to five adverts funded by Catskill Citizens for Safe Energy which will begin airing in New York on Tuesday (30Oct12).

Hydrofracking, or fracking, is a process whereby chemically-induced liquids are injected directly into deep underground rock in order to extract natural gas and oil, and Redford is appealing for listeners to protest against it.

In one advert he states, "This is Robert Redford. New York faces an urgent decision: Whether to begin hydraulic fracking, a process that blasts toxic chemicals into the ground to release natural gas. It would be a dangerous mistake. Fracking is a bad deal for local communities."

The Sting star adds in a statement, "It turns out that fracking for gas threatens drinking water supplies, contaminates the air and contributes to climate change. To make matters worse, the gas industry plans to ship much of our shale gas overseas, as we shoulder all the environmental and public health risk."

Redford is not the first celebrity to speak out to condemn fracking - actors Matt Damon, Richard Gere and Alec Baldwin have already added their voices to the campaign.