Sen. Barbara Mikulski (D-Md.) (Chip Somodevilla/Getty Images)

A proposed wind farm on Maryland’s Eastern Shore again faces the threat of a potentially project-killing delay because of worries that the whirling turbines could threaten a sensitive radar system at the nearby Patuxent Naval Air Station.

U.S. Sen. Barbara A. Mikulski (D-Md.), chairman of the Senate Appropriations Committee, has added language to the defense appropriation bill that could prevent the Navy from finalizing an agreement with the wind farm developers until researchers finish a study of the effects of the turbines and what could be done to mitigate them.

The study by MIT’s Lincoln Laboratory is scheduled for completion by next summer. Waiting until then would mean that Pioneer Green Energy, the company proposing the wind farm, would have to redo studies required to obtain permits and could miss a deadline to qualify for federal tax credits. Company officials have said for months that a significant delay would effectively kill the project.

The Appropriations Committee approved the bill with Mikulski’s language in July, but the bill has not gone to a vote on the Senate floor. The House of Representatives passed a defense appropriations bill earlier this year that did not include the language.

Legislation passed in Maryland’s General Assembly this year also would have delayed the project until after the MIT study was finished, but Gov. Martin O’Malley (D) vetoed that bill in May. The governor said at the time that there are already safeguards in place to protect the military base from the risks and concerns raised by opponents.

O’Malley also said the legislation would send “a chilling message” to the clean-energy industry if it became law. By 2022, Maryland wants 20 percent of its energy to come from renewable sources, a goal that would be most easily accomplished by increasing the number of renewable energy sources within the state.

A spokesman for O’Malley declined to comment on Mikulski’s legislative move.

Pioneer Green Energy has proposed spending $200­ million to build at least 25 turbines in Somerset County. The project promises hundreds of construction jobs, and farmers who host turbines could get extra income.

But the whirling blades would interfere with a sensitive radar system that’s used to test the stealthiness of fighter jets at the base, commonly called Pax River. The base sits across the Chesapeake Bay from where the wind farm would be created.

The developers offered to turn the turbines off during test flights, an idea they say received initial approval from military leaders. Lawmakers who represent the area say that’s not a sufficient solution, however.

Some of the most vocal opponents of the wind farm are members of Maryland’s congressional delegation, including House Minority Whip Steny H. Hoyer (D), whose district includes Pax River. Hoyer urged military officials not to sign an agreement with the developers and testified in Annapolis in favor of the state legislation that would have delayed the project.

Mikulski and Sen. Benjamin L. Cardin (D-Md.) joined Hoyer in a letter to local lawmakers supporting a delay. Rep. Andy Harris — who represents the Eastern Shore and is Maryland’s lone Republican in Congress — also has raised concerns about the project, which he says wouldn’t provide the economic boon to the region that developers have promised.

Adam Cohen, a Pioneer Green Energy founder and vice president, said that he expects the Navy to continue to work toward an agreement despite the language that Mikulski added to the appropriations bill. He said that federal law requires the military to cooperate with alternative energy developers, which he believes outweighs the mention of the project in the appropriations bill.

“The language inserted by Senator Mikulski is not an appropriate reason for delay in the Navy putting its final signatures on our agreement,” Cohen said in a statement. “It’s time for this agreement and our project to move forward.”