The Marcellus Shale has generated superlatives from all sides of the debate on shale-gas development.

For the booming industry, the massive natural gas play, stretching from New York to Virginia, is a “game changer” that will reduce US dependence on imported oil, cut greenhouse gas emissions, and generate thousands of jobs.

For opponents of the “fracking” technique that is enabling huge quantities of gas to be harvested, the Marcellus represents a threat to public health by allegedly contaminating ground water with toxic chemicals used in the extraction technique.

Although state and federal officials are investigating claims that the field’s potential has been overstated, there’s little doubt that it’s a major domestic energy source that is still in its infancy.

Breaking Energy has been running a series of top fives throughout this week and last, which can all be found with the image (top) and the ‘Top5′ tag. Read the other Top Fives: Top Five DOE Recovery Act Loans, Top Five Electric Vehicle Partnerships, Top Five Clean Energy VCs And Principals, Top Five International Energy Partnerships, Top Five Energy Regulators, and Top Five Energy Law Firms.