PITTSBURGH — A trade group that represents small, independent gas and oil producers in Pennsylvania has filed a lawsuit challenging new state regulations for conventional drilling.

The Pennsylvania Independent Petroleum Producers Association of Bradford says the rules would be financially ruinous.

A newspaper reported Thursday the suit argues the Department of Environmental Protection unfairly grouped conventional drillers, which target shallow formations, with unconventional drillers that concentrate on the deeper Marcellus Shale.

The trade group is trying to block the rules before April 21, when a review board is scheduled to vote on them.

The suit was filed in Commonwealth Court. A DEP spokesman declined to comment.