The 30-day comment period for revised regulations for shale gas drilling using hydraulic fracturing, or fracking, ends Friday. Numerous environmental groups and elected officials from around the state have called on Cuomo to suspend the comment period until regulations are revised to reflect the health impact review findings. Fracking is under moratorium in New York until the debate is resolved.

"If the public is to provide meaningful comment on the proposed regulations, the public should be able to see the studies and analysis that were produced at public expense," read the letter sent to Cuomo by Assembly Environmental Conservation Committee Chairman Robert Sweeney, Health Chairman Richard Gottfried and Regulation Review Chairman Charles Lavine.

Fracking, a technology that releases gas from shale by injecting a well with millions of gallons of chemically treated water and sand, has made it possible to tap into deep reserves of oil and gas but has also raised concerns about pollution. Regulators contend that water and air pollution problems are rare, but environmental groups and some scientists say there hasn't been enough research on those issues.

The technology has drawn intense scrutiny since the focus of gas drilling companies has shifted in recent years to the Marcellus Shale, a massive rock formation underlying New York, Pennsylvania, Ohio and West Virginia.

The three chairmen are holding a public hearing Thursday on the New York regulations and have asked Department of Environmental Conservation Commissioner Joseph Martens and Health Commissioner Nirav Shah to attend and bring all information provided to the three outside experts asked to review DEC's health impact analysis.

They also called on the Cuomo administration to disclose all materials related to the health study requested under the Freedom of Information Law by Environmental Advocates and others. The Associated Press submitted FOIL requests to Cuomo's office and the health and environmental agencies in September seeking documents and communications related to DEC's review of the health impacts of shale gas development, but no documents have been provided so far.

Under state law for making new regulations, DEC had a deadline of Nov. 29 to finalize its rules for fracking. DEC filed for a 90-day extension to allow time for a health impact review to be completed.

If the new deadline at the end of February is missed, DEC would have to reissue regulations and hold public hearings, potentially adding months onto an environmental impact review that started in July 2008. Shale gas development has been banned in New York since the review began.

DEC spokeswoman Emily DeSantis said agency personnel won't attend the Assembly hearing, noting that the agency has already participated in three Assembly hearings. But she said DEC will consider comments submitted at the hearing as it continues its environmental review.

"DEC will not take any final action or make any decision regarding hydraulic fracturing until after Dr. Shah's health review is completed and DEC, through the environmental impact statement, is satisfied that this activity can be done safely in New York state," DeSantis said via email.