ALBANY, N.Y. (AP) — The Environmental Protection Agency said New York regulators have much more work to do on proposed regulations that have already held up gas drilling in the state’s part of the massive Marcellus Shale formation for more than a year.

The EPA submitted its comments Wednesday on the state Department of Environmental Conservation’s 809-page draft document that sets rules for gas drilling using high-volume hydraulic fracturing. The controversial technique, which injects chemical-laced water into deep horizontal wells to release gas from shale, has raised concerns about potential contamination of drinking water.

The EPA said the draft, released at the end of September for a public comment period ending Dec. 31, needs to significantly expand analysis of cumulative impacts of gas exploration and place greater emphasis on potential health effects.

In addition, the EPA expressed “serious reservations” about whether gas drilling should be allowed in the New York City watershed in southeastern New York. Mayor Michael Bloomberg’s administration has asked the DEC to ban drilling in the watershed, which provides drinking water for 9 million people.

The EPA recommended that the state Health Department, which enforces the Safe Drinking Water Act, and Public Service Commission, which oversees natural gas pipelines, collaborate with the DEC on the regulatory document.

The agency said it was particularly concerned about issues involving water supply, water quality, wastewater treatment, air quality, and management of natural radioactive materials disturbed during drilling.