COLUMBUS, Ohio — Ohio, West Virginia and Pennsylvania on Tuesday agreed to co-operate in attracting shale gas development and jobs to their region over the next three years rather than compete with each other.

The states signed an agreement during the Tri-State Shale Summit in Morgantown, West Virginia. They said they've agreed to co-ordinate marketing efforts, workforce development, investment strategies and academic research as they capitalize on Utica and Marcellus shale development "in an environmentally sound manner."

Shale gas has become available by an extraction process commonly known as fracking, which involves high-pressure mixtures of water, sand or gravel and chemicals injected into the shale to crack open the rock layers and free the gas. Environmentalists and other critics say fracking could contaminate water supplies, but the energy industry says the process has been used safely for years.

The U.S. Energy Information Administration reports the three states have had 85 per cent of the increase in U.S. natural gas production since January 2012.

Ohio Lt. Gov. Mary Taylor said challenges and opportunities surrounding the industry don't recognize state lines so collaboration is essential.

"We are seeing tremendous and continued growth in this industry, and we know that can be strengthened by partnering on key areas," Taylor said.

The agreement calls the three-state area "an emerging world-class energy centre."

As part of the agreement, the three neighbouring states also will discuss ways to work together to attract new businesses, spur investments in expanding delivery of gas and liquids and encourage their academic institutions to expand and collaborate on research.

Julie Carr Smyth, The Associated Press