HARRISBURG — The largest organization representing companies involved in Pennsylvania’s natural gas drilling boom waded into gubernatorial politics Thursday and attacked proposals to raise taxes on the industry by various would-be Democratic challengers to Gov. Tom Corbett.

The Marcellus Shale Coalition issued a statement criticizing tax proposals it said were being touted by some gubernatorial candidates. A spokesman later pointed to statements by six different candidates seeking the Democratic Party nomination favoring similar severance tax proposals that could raise more than $1 billion a year from the industry.

The coalition statement warned companies would take their money to other states. “It would be irresponsible and ill-advised to advance massive new energy taxes that would strike an unnecessary blow to one of our economy’s most important, thriving and promising sectors,” the statement said.

Corbett, a Republican widely viewed as a strong industry ally, fought proposals to slap a tax or a fee on the booming industry before agreeing in 2012 to an “impact fee” that is currently generating about $200 million a year for state programs and drilling communities.

The Corbett campaign, regarding U.S. Rep. Allyson Schwartz as the leading Democratic contender, has attacked her recent proposal to add a 5 percent tax to the value of gas produced from Pennsylvania’s Marcellus Shale.

Pennsylvania does not currently tax gas production. Many other states impose a grab bag of taxes or fees. But the Marcellus Shale Coalition said such a tax in Pennsylvania risks hurting investment and hiring. Democrats say a severance tax would bring Pennsylvania in line with other states.