Two more environmental groups have begun to push for strengthened state regulation of the shale gas industry, asking for 50 amendments to the state Oil and Gas Act.

The Pennsylvania Environmental Council and the Chesapeake Bay Foundation released their recommendations on Tuesday that include:

-- An expanded permit process to increase public review and comments.

-- Prohibitions on drilling in flood plains.

-- Wider buffers between wells and waterways.

-- Higher bond requirements so drillers would set aside more money to cap wells and insure against wear and tear.

"The regulations and oversight governing this industry have not kept up with the technology for extraction," said Matt Ehrhart, executive director of the Chesapeake Bay Foundation's Pennsylvania office.

Last week, Philadelphia-based PennEnvironment released its own recommendations.

Pennsylvania Environmental Council and the Chesapeake Bay Foundation gave their proposals to several state legislators and Gov. Tom Corbett's Marcellus Shale Commission, which is meeting to discuss how to regulate and encourage the growing industry.

Range Resources Corp. has spent time talking with the Pennsylvania Environmental Council about the recommendations, a company spokesman said.

"A lot of their recommendations make sense," spokesman Matt Pitzarella said in an e-mail. "Natural gas development won't be sustainable without partnership and public trust, so anything that promotes meaningful discourse is helpful."