ALLENTOWN, Pa. (AP) -- Federal environmental regulators are questioning the rationale of a proposed 39-mile natural gas pipeline that opponents say would damage 600 acres of pristine forests and streams in northern Pennsylvania's Endless Mountains region.Central New York Oil and Gas Company LLC is seeking regulatory approval to use eminent domain, if necessary, to acquire land for its MARC 1 pipeline in Bradford, Sullivan and Lycoming counties. The pipeline could open new areas to drilling and would connect with three existing interstate pipelines to take natural gas produced from the giant Marcellus Shale formation to market.In written comments this week, the federal Environmental Protection Agency said it's not clear why the MARC 1 needs to be built at all, given existing pipeline infrastructure."It is difficult to understand why natural gas distribution could not be accomplished in the absence of the MARC 1 line," the EPA's Philadelphia office wrote, adding that New York Oil and Gas itself has said that other pipelines are capable of transporting gas from the Marcellus.The agency noted the pipeline would cross more than 100 waterways, result in the loss of more than 200,000 mature trees, and said it had questions about the possible effect on "water quality, aquatic resources, air quality, wildlife and their habitat and forested landscapes, among other environmental and cultural values" in the area popular with tourists.The EPA submitted its comments to the Federal Energy Regulatory Commission, which must approve the pipeline project. FERC staff have already found the pipeline would have "no significant impact" on the environment and recommended that it be allowed to go forward.But the EPA said the commission analysis "does not clearly explain to the public why the existing gas pipeline distribution network is not sufficient for providing access to interstate markets for Marcellus Shale natural gas, and why a new pipeline ... through largely undeveloped and forested land needs to be constructed."FERC spokeswoman Tamara Young-Allen declined comment on the EPA remarks but noted that all comments are taken into consideration. The five-member commission could vote on the MARC 1 project by the end of the year.FERC has received more than 20,000 comments on the pipeline proposal, many of them demanding that construction be delayed until a more thorough environmental review is undertaken.A spokeswoman for the pipeline company did not immediately return phone and email messages Thursday. Central New York Oil And Gas is a subsidiary of Inergy LP of Kansas City, Mo.